The boys are way into Chuck Norris jokes these days; apparently they're all the rage right now at school (last year it was "your momma" jokes).
Andrew (12) generally gets the genre and has come back from school with a few good ones like "Chuck Norris counted to infinity. Twice." or "When Chuck Norris jumps into the water, he doesn't get wet. The water gets Chuck Norris'ed."
Michael (9) doesn't quite understand what makes these funny but is still trying to make up jokes, like "Chuck Norris doesn't rob banks. He just walks in and they give him the money." We'll have to keep working on this with him.
Here's a list of funny ones I found. A few of my favorites:
"Chuck Norris doesn't breath. He holds air hostage."
"When the boogeyman goes to sleep, he checks his closet for Chuck Norris."