Okay, I know Chuck Norris jokes are a little past their prime, but most gamers will appreciate this list (and since I wrote these, I don't need no stinkin' attribution):
Chuck Norris doesn't roll the dice. He kicks the world, and the trembling causes the dice to roll by themselves.
Figure manufacturers stopped using lead because it melted too easily when exposed to Chuck Norris's glare.
Chuck Norris's d20 doesn't stop at 20. It stops at Chuck.
Percentile dice rolled in Chuck Norris's presence never roll "00". Chuck Norris is the only thing in the universe that is 100%.
Chuck Norris has his own special saving throws. They're called "throwing a punch" and "throwing a kick".
Each and every skull on all the Warhammer 40K products in the world is dedicated to a specific victim of Chuck Norris.
Chuck Norris carries his own blast template, which he is allowed by law to use in any game he plays. It's the size of Fear and made of Pain.
A Chuck Norris unit on the game table has one attack, the Roundhouse Kick. It has a 100% chance to hit and a 1,000% chance to kill the other player, the other player's neighbors, the other player's ancestors for the past 300 years, and Osama bin Laden.
Chuck Norris doesn't use rule books. He brings blank paper and the rules write themselves around him.
By the time you say the words "Roll for initiative", Chuck Norris will already have won the game and kicked your spleen out through your back, to boot.
If Chuck Norris were the Emperor in Warhammer 40K, he would simply roundhouse kick Chaos hard enough to fling them back through the Warp and cauterize it closed. Then he would eat the Tau and use the Tyranids as compost.
Chuck Norris has a character sheet with only one block on it. It says simply "Chuck Norris" and trumps all other attributes.
Chuck Norris doesn't paint minis. He simply glares at them and they hurriedly paint themselves.
When Chuck Norris plays ancients, he demands that the little pikemen have their pikes coated with curare. The loser has to eat them. However, Chuck Norris doesn't lose, ever.
Chuck Norris doesn't need dice, since he invented probability (as in, "there's a 100% probability of roundhouse kick-related pain in your future").
The words "war", "blood", "pain", "kick", and "fighting" are all copyrights of Chuck Norris, requiring all games using them to pay him royalties.
Source books are called "splatbooks" because of what Chuck Norris once did to some of their authors.
Chuck Norris can make lead minis bleed and plastic minis cry.
When Chuck Norris plays Axis & Allies, France really surrenders.
The Chuck Norris die has only one face. It's Chuck Norris's, and it always wins.