Recently I completed a 'weighted companion cube' for him (which is from another of the brilliant designs by nerdigurumi). If you've not heard of the game Portal then it may seem a little strange to take the time to crochet a cube - but believe me it is a fantastic game and this little inanimate cube has a big fan following and so has quite a few free crochet patterns as well as some pretty amazing reproductions - just type 'weighted companion cube' into a google image search and prepare to be impressed.
Most recently I have just finished up a much quicker pattern for one of the birds from the 'angry birds' game which my husband plays on his iPhone. This game involves catapulting some kamikaze birds into some fortified pigs with hard hats - strange but oddly addictive. If I had more time then I would give making one of the green pigs a go so that Rich could have something to target his new angry bird at - perhaps I'll get round to it later in the year - along with all the other cool but geeky patterns that I want to try...
Slime from the Dragon quest games
Lemmings
Mario mushrooms