So in my AP biology class the other day, we were getting really off topic...
Dr. Looney: *rings cow bell to get us to shut up*
Dr. Looney: You know, students are kinda like cows - one strays, the rest follow.
Ryan: You mean we're udder joys to teach?
Katy: C'mon Dr. Looney, you gotta milk it for all it's worth!
...AP biology, ladies and gentlemen.