Why'd the rubber go flying across the room?
Because it got pissed off!
Pissed Off Condom
Explanation
Explain Bear
Listen up, buttercup. The joke is that "rubber" is slang for condom. And "pissed off" means angry. So, the joke is a condom flew across the room because it got angry. See, it's funny because condoms don't have feelings, just like you don't have brains.