I was thinking about comedy today, specifically, about a line in the Simpsons that  really cracks me up.  It's the episode where Homer gets sent to a small island in the Pacific as a missionary, and Bart has to go to work at the nuclear power plant.  Bart's sitting at Homer's desk and Mr. Burns come in to berate him.  He reads off a list of grievances and then says, "And worst of all, you took the Hamburgler's birthday off last Monday *and* Wednesday.  Which is it?"
This line is genius.  It has three levels of comedy:
Level 1:  "You took the Hamburgler's birthday off last Monday".  Okay,  mildly amusing;  comedy 101.
Level 2:  "You took the Hamburgler's birthday off last Monday *and* Wednesday."  Much funnier.
Level 3:  "You took the Hamburgler's birthday off last Monday *and* Wednesday.  Which is it?"  Now THAT is comedy.