Do you cross-train your brain? If so, how?

I like to play scrabble with my wife. She's quite a good player. But her mother flat-out destroys the both of us when we are visiting!

What do you do to sharpen your mind for chess?

Mostly chess ;). 

That's a good question. Two things I've been wanting to do that I imagine would help a lot is mental math and meditation. These would help with snap-like reactions / taking a mental picture and allowing deep, uninterupted thought, respectively.

Ahh I love scrabble, but I only play it a couple times a year when I visit my dad.  Maybe I should start playing it onliine...  I'm with ih8sens though, all I do to sharpen my mind is play many many games of chess.  I should probably branch out a bit more.

http://www.chess.com/groups/home/the-brain-strainers-of-chesscom

This is an excellent group for exactly that purpose. Not sure if non members can access forums of groups they don't belong to, but if you can, check out the posts about airplane refuelling. Kept us occupied for days....