gotoAndPlay("outside")
This t-shirt might not mean anything to anyone, other than a flash/actionscript programmer but it is particularly relevant to any one who uses actionscript or flash regularly. The command gotoAndPlay moves to a frame in the flash movie, so if there was a frame called outside then it would go to that frame, so to anyone else it is just cute because it says to go and play outside. 
http://www.cafepress.com/+gotoandplay_outside_white_tshirt,102114845
Tags: actionscript, cafepress, flash, flash actionscript, geek, gotoandplay, movie, nerd, programmer, T-Shirt, tshirt