Donald Trump is President of the United States. Or an even shorter version: Donald Trump.

(you said it doesn't have to be funny)

Ok here's a good one:

Q: How many mice does it take to screw in a light bulb?

A: Just two, but damned if I know how they got in there.

Or may favorite joke ever..: A priest, a rabbi, and a minister walk into a bar. The bartender says, "What is this, a joke?"