PICARD (to RIKER): Pull my finger.
RIKER: No way; I've seen this one before.
PICARD (to RO): Pull my finger.
RO: You're a disgusting old man, you know that?
DATA: ... so he said, "woah there Doc, I'm no brain surgeon" and she said, "don't worry, neither am I", and then they just cracked her open and got to work.
RIKER: Hmm, well, it sure sounds like the start of a joke, but I don't think we're going to get a funny ending.
PICARD: You might want to give it a few minutes before going in there.
Lost TNG Episode #184: The crew get trapped within a mysterious alien snowglobe. Troi attempts to communicate telepathically with it, with unexpected but hilarious consequences.