Here's another appalling racially-stereotypical joke involving Irishmen, suitable for the under-12s.
Paddy and Mick go into a pet shop and buy two budgerigars. They drive out to a local clifftop, where Mick holds a bird in each hand, gives Paddy a knowing wink, and jumps off the cliffs. He sails into mid-air for a few seconds before hurtling down onto the beach below, where he's well mashed.
"Oh, shoite," cries Paddy, aghast. "That's the last time we'll try that!"
A few weeks later, Paddy's back at the cliffs with Sean. Sean is armed with a parrot and a shotgun. With Paddy's encouragement, he approaches the cliff edge, hurls the parrot over it, then takes a flyer at it himself, blasting away at the parrot on the way down to the beach below, where he, too, is well mashed.
"Aw, no, no!" Paddy bawls, aghast again. "What a mess! That'll be the last time I help poor Sean with that."
A couple of months later, Paddy's back up at the cliffs, this time alone. He is clutching a fat chicken in his hands, and takes a running jump off the cliff. The chicken flies squawking out of his hands, airborne for the first time in her life, while Paddy crashes into the seaweed and foam below. He's fairly battered, but manages to swim to the shore, where an astounded lifeguard rushes to help him.
"That's it! That's it!" bellows a furious Paddy, spitting out sand. "I've had it with all dem stupid sports! Me mates are in the hospital after the budgie-jumping and the parrotshooting, and that's me done with the hengliding!"