Heh.
I always liked...
quagmire: hey how old are you?
some girl: 16.
quagmire: 18? You're first.
girl: Mom!
quagmire: I like where this is going!
and this one cracks me up,
"woah transvestite back off! wait a minute...pre-op or post-op?"
"pre-op"
"woah transvestite back off!"