There are some brilliant ones on Tumblr...
http://tomfowlerddd.tumblr.com/image/38437893265 R.I.P
http://ajsdraws.tumblr.com/post/39979094812/guys-if-you-have-even-the-most-marginal-interest
http://guytensen.tumblr.com/post/39412667537/quick-drawing-based-upon-episode-5-of-nerd-poker