Xiaolin Showdown was probably one of the only show worth watching in the entire Kids WB! programming block. It had a good plot, great character development, surprisingly well thought out action, and was genuinely funny - it even had some pretty dark humor worked in there. Of course, since it was good, that means it had to get canceled.
"Haha, four eyes!" "Jack, he's blind." "Oh, even better. Haha, no eyes!"
As for the games... A friend of mine tried out the PS2 game. It was crap. I'm gonna bet all the other ones are too.
As for the dots on Omi's head? That's a common thing with tibetan monks though I forget the signifigance. I believe it has something to do with the flow of chi through the body.