Stupid jokes

Have you ever come across a joke that just DOES'NT MAKE SENSE LIKE, AT ALL?!?!?!?!?!?!?!
Well, I have. PLENTY of times. Its strange, you would think those jokes wouldn't make you laugh, but the jokes are just so... so... STUPID you end up laughing anyway.

Here's a bunch of jokes I found in a magazine that don't even make SENSE:

What's purple and smells like paint?
Purple paint! Ha. Ha. Ha. Ha. Ha... :()

Knock knock!
Who's there?
Your underwear.

What does Tarzan say when he sees a herd of elephants in the distance?
Look, a herd of elephants in the distance

What's red and invisible?
No tomatoes

Why isn't it safe to climb oak trees between 2 and 4 in the afternoon?
Because that is when the elephants practice their parachute jumping.

Why did Jack fall off the bike?
Because he was a fish.

It's sooooooooo weird, because sometimes really stupid jokes make you crack up. If anyone else has some stupid jokes, or jokes that hardly make sense, leave a comment...