From a Q&A session with Mr. Know-It-All on Wired magazine:

Q: My son is finally old enough to play Halo 3 with me. Should I let him win sometimes or just crush him as I would any other inferior opponent?

A: If you’re honestly thinking of obliterating your kid in Halo 3, it’s time to return all that “World’s Number One Dad” merchandise. Turning your death matches into 30-second routs will only sour the boy on gaming. And it won’t be all that fun for you either. That said, you also shouldn’t take dives: You want to give your son an incentive to keep sharpening his skills. When the boy lucks into a nice move, for example, take a moment to offer praise before shotgunning him in the face. And when you execute a coup de grace, do it with grace– teach the kid to be a good sport even as you demonstrate the finer points of wielding the gravity hammer.

Heh. Sometimes I feel that way playing Warzone against Alex and Zack.