"Fruit flies like a banana" usually follows the set-up "Time flies like an arrow." So the setup to Nick's joke was actually a punchline he borrowed from another joke. And I've got to say his joke was diggity-dang good.
my favorite mashup so far is "Dirty Bottle" Aguilerra's "Genie in a Bottle" and Sonic Youth's "Dirty Boots", which is absolutely transcendent. Though the Missy Elliot/Blondie one is pretty cool too.
"Tits like coconuts, but starlings prefer breadcrumbs". SO SO SORRY
Lore wrote a big ol' bunch of them: <a href="http://www.brunching.com/afterpunchline.html">After the Punchline</a>.