bundles - why do you buy them?

i realised how many bundled games and games on steamsales i bought - well actually just to have them in my library. it's kinda weird but i already know that i wont play most of the games before buying the bundle except some huge titles like alan wake, sniper elite v2 or the walking dead. well at least some bucks are going to charity xD how many bundles have you bought and how much money have you spent on them?