Thanks to Oz Packer Backer's cheese page for this one. there are some other good ones at their page:
http://olympia.fortunecity.com/white/225/fcheese.htmA Packer fan in a bar leans over to the guy next to him and says, "Wanna hear a joke about Viking fans?"
The guy next to him replies, "Well before you tell that joke you should know something. I'm 6' tall and 220 pounds and I'm a Viking fan. The guy sitting next to me is 6'2" tall, 240 pounds and he's a Viking fan, and the guy sitting next to him is 6'5", 280 pounds and he's a Viking fan too. Now, do you still wanna tell that joke?"
The Packer fan says, "Nah, not if I'm gonna have to explain it three times."