I'm not much of a contributor to MathOverflow, but I do love to check in and read the different postings. But one thing that is awesome about MathOverflow that I have never heard talked up before is the amazing display of humor I see here. Would anyone be interested in a side project of compiling The Best Humor of MathOverflow? I will understand if others find my request impertinent. On the other hand I would understand if some of the responses to this question were somewhat humorous themselves.

After my modest attempt regarding your side request. I will mention the selection of highly voted comments Akhil Mathew compiled; a considerable proportion of which fall into the category your search, see http://people.fas.harvard.edu/~amathew/greatMOcomments.html

Edit: I just rechecked, perhaps 'considerable proportion' is an overstatment; some are, but more are really mathematical or otherwise insightful, still I think it is worth a look also for your purpose.

Some more humour in comments that really cracks me up: Kevin O'Bryant's comment to this answer; Kevin Buzzard's answer and the following two comments.

I will probably remember some more and add it here.