Stalin had a particular sense of humor, specific, but very witty. Sometimes he voiced his decisions and inferences with humor, but ones to whom he said it were rarely amused. 

1. About cars

During  the designing of the car "Pobeda" (Victory - in English) it was planned that the car name will be  "Rodina" (Motherland - in English). Stalin found out about this and ironically asked: "So how much is our Motherland?" The name of the car was changed immediately.

2. About his guard

From the memoirs of one of Stalin's bodyguards. Stalin in his trips was often accompanied by a security guard by the name of Tukov who was sitting in the front seat beside the driver, and used to fall asleep on the way. Someone from the members of the Politburo, who was riding in the car in the back seat with Stalin, said:
– Comrade Stalin, I don't understand who of you is a guard of whom?
– I have no idea,– said Stalin, – He even stuck his gun in my raincoat – Take, he says, just in case!

3. About Love

Once Stalin was told that Marshal Rokossovsky had a mistress and she is a well known beautiful actress Valentina Serova. And, Stalin was asked: "What we will do now with it?" Stalin took the pipe from his mouth, a little thought and said:
— What will we do, what will we do?... We'll be jealous!

4. About import substitution

Stalin was walking with the First Secretary of the Georgian Central Committee of Communist Party A. I. Mgeladze through the alleys of the Kuntsevo dacha, and treated him with lemons that he grew in his garden:
- Try them. They grew up here, in Moscow! 
And so several times between the conversation on to other topics:
- Try it, lemons are good! 
Finally, the interlocutor came up with:
– Comrade Stalin, I promise you that after seven years, Georgia will provide the country with own lemons, and we will not import them from abroad any more.
– Thank God, you guessed! – said Stalin.

5. About the merits

The designer of artillery systems V. G. Grabin told me that on the eve of 1942, Stalin invited him and said:
– Your gun saved Soviet Union. Whan will you choose - a Hero of Socialist Labor, or the Stalin prize?
- I don't care, comrade Stalin.
He was rewarded with both.

6. About boasting

During the war, troops under the command of Baghramyan were the first who came to the Baltic. To present this event with a pathos, the Armenian General personally, filled a bottle with a water from the Baltic sea and ordered his adutant to fly with this bottle in Moscow to Stalin. He flew. But while he was flying, the Germans counterattacked and drove Baghramyan from the Baltic coast. By the time of arrival of the aircraft in Moscow had already been aware of this, and the adjutant did not know about it — there was no radio in the plane . 
A proud adjutant's comes to Stalin's office and says: 
— Comrade Stalin, General Bagramyan sends You the water of the Baltic sea! 
Stalin takes a bottle, a few seconds twirls it in his hands, then gives it back and says: — Give back this to the General Bagramyan, tell him to pour out this where he took it.

7. About the most important of the arts

In 1939 Stalin watched a movie "The Train goes East". The movie was tedious: train rides, stops...
— What station is that? – asked Stalin.
— Dem'ianivka.
— This is where I get off, – said Stalin and left the room.

8. About knowledge of the measure

Discussed the candidacy for the post of Minister of the coal industry.
Suggested Zasyadko, Director of one of the mines. Someone said:
— All right, but he is abusing alcohol!
— Invite him to me, – said Stalin. Came Zasyadko. Stalin began to talk with him and offered a drink.
— With a pleasure,–  Zasyadko said, poured a glass of vodka: – Your health, comrade Stalin! – drank and continued the conversation.
Stalin drank a little and, watching carefully at his guest, offered another toast. Zasyadko drank a second glass, and still sober. Stalin proposed the third toast, but his companion pushed his glass aside and said:
— Zasyadko knows the measure. 
So they talked on. Later at the Politburo meeting, when again the question about the nomination of the Minister arose, and again it was stated about the abuse of alcohol by the proposed candidate, Stalin, walking with his famous pipe, smiled and said
— Zasyadko knows the measure!
Then Zasyadko was appointed and for many years headed Soviet coal industry...

9. About impudence

One Colonel-General, reported to Stalin about the situation. Supreme commander looked very pleased and nodded twice. Upon completing the report, the chieftain
hesitated. Stalin asked: "Do You want anything else to say?"
"Yes, I have a personal question. In Germany, I have selected some things interesting for me, but they were detained at the checkpoint. If possible, I would ask you to return that staff to me."
- We can do that. Write me a report, I will impose a resolution."
Colonel-General pulled out his pre-prepared report. Stalin imposed a resolution. Petitioner began warmly thanking.
— Don't mention it, - said Stalin.
Then the officer reads the resolution on the report: "Give back the stuff to the Colonel. Joseph Stalin". The General appealed to the Supreme: 
— Here is a typo, comrade Stalin. I'm not a Colonel, but a Colonel-General.
— No, it's all right, comrade Colonel, - replied Stalin.

10. On the requirements for employees

Admiral Isakov in 1938 was a Deputy people's Commissar of the Navy. One day in 1946, Stalin invited him and said that there is an oppition to appoint him at a position of a chief of Naval staff.
Isakov said: 
— Comrade Stalin, I must report that I have a serious drawback: one leg amputated.
— Is this the only drawback, which you consider necessary to report? – a question followed by .
- Yes, - confirmed the Admiral.
- We used to have a chief of staff without a head. Nothing, it still worked. You just have no leg – it's not a problem, - concluded Stalin.

11. On corruption

After the war, Stalin learned that Professor K. has built a very expensive house near Moscow. Stalin called for him and asked: 
— Is It true that you built a house for so many thousand?!
— The truth, comrade Stalin, - replied the Professor. 
— Thank you from the orphanage, to whom you gave your home, — said Stalin and sent him to teach in Novosibirsk.

12. About the foreign press

In the fall of 1936 in the West was spread the rumor that Joseph Stalin died from a serious illness. Charles Nitter, the correspondent of news agency  Associated Press, decided to obtain information from the most reliable source. He went to the Kremlin, where gave a letter for Stalin in which he asked to confirm or deny this rumor. 
Stalin replied the journalist immediately: 
"Your Majesty! As far as I know from the reports of the foreign press, I long ago left this sinful world and moved to the next world. Since the reports of foreign press can not be disregarded, if you do not want to be struck from the list of civilized people, then I ask you to believe these reports and not to disturb my peace in the silence of the other world.
October 26, 1936. Yours sincerely, J.Stalin".

13. About heraldry

Once a foreign correspondent asked Stalin:
– Why on the coat of arms of Armenian Republic a mount of Ararat is depicted, but it is not on the territory of Armenia.
Stalin replied:
– The emblem of the Turkish is a Crescent, but the Moon is not on the territory of Turkey too.

14. About the regulations of speeches

The People's Commissar of Agriculture of Ukraine was summoned to the Politburo, He asked:
- How should I report: briefly or in detail?
- As you like, you can briefly, you can detail, but the time limit is three minutes, - Stalin replied.

15. About the opera

The Bolshoi Theater was preparing a new performance of Glinka's opera Ivan Susanin. The members of the commission, headed by Chairman Bolshakov, listened and decided that it was necessary to withdraw the finale of "Glory to the Russian people!": Ecclesiasticality, patriarchalism ...
Reported to Stalin.
- We'll do slightly different: we'll leave the finale, but we'll remove Bolshakov.

16. Prioritization

When the Allies decided what to do with the captured Nazi navy, Stalin offered to divide, and Churchill made a counter offer: "To sink." Stalin replies: "Here is your half - you may sink it".

17. About pseudonyms

Stalin came to the play in Art theater. He was greeted by Stanislavsky and, holding out his hand, said: "Alekseev," calling his real name.
"Dzhugashvili," Stalin replied by his real name, shaking his hand, and walked to his chair.

18. About ambitions

Harriman at the Potsdam conference asked Stalin:
- After the Germans in 1941 were 18 km away from Moscow, probably, now you are pleased to share the defeated Berlin?
- Tsar Alexander reached Paris, - Stalin replied.

19. About weather forecasts

Stalin asked meteorologists what percentage of the accuracy of forecasts they had.
- Forty percent, Comrade Stalin.
- Say the opposite, and then you will have sixty percent.

20. About diligence

During the war, Stalin instructed Baibakov to open new oil fields. When Baibakov objected that it was impossible, Stalin replied:
- If will be oil - will be Baibakov, will be no oil - will be no Baibakov!
Soon there were discovered deposits in Tataria and Bashkortostan.