My favorite source of one-liners (and two-liners) is comedian Steven Wright. Examples:

"The sign in the restaurant said, 'Breakfast any time', so I said 'I'll have French toast during the Renaissance.'"

"Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before."

"I went to a general store. They wouldn't let me buy anything specifically."

There are dozens of web sites that list these. Use your search engine to find them.