What did one sushi say to the other?
Wassaaaaabi!
What did the fish say when he swam into a wall?
Dam.
A neutron walks into a bar and asks the bartender how much for a beer. The bartender replies, "for you? No charge".
A mushroom walks into a bar and the bartender says, "I'm sorry, we don't serve your kind here". The mushroom replies, "Why not? I'm a fungi!"
What do you call a judge with no thumbs?
Justice fingers.
And one of my favourites which you will need an odd sense of humour for, and advance apologies to Koalafan:
Why did the koala fall out of the tree? Because it was dead.
Why did the second koala fall out of the tree? Because it was stapled to the first koala..
Why did the third koala fall out of the tree? Because it thought it was a race to the bottom.
Why did the fourth koala fall out of the tree? Peer pressure.
Why did the Australian fall off his bike? Because he was hit by 4 koalas.