As a guy, a man married to the same woman for 22 years, and the father of an 18 year old daughter whom has dated a few guys -- I want to offer this "guide to guys".
Girls seem to think guys are difficult to understand, but really, most guys are fairly simple. Most guys are driven by a few things but not necessarily in this order:
(2) Play (games, sports, whatever)
(3) Sleep (mainly naps)
After that, guys can be broken down into types (mix and match too):