"orz" is a geeky emoticon. It takes the following forms

orz ORZ OTL

They're supposed to look like a person on their hands and knees with their head hung down, in a despairing pose; "orz" the term is generally used to signify some kind of capitulation or humorous despair. (More info (http://en.wikipedia.org/wiki/Emoticon#Posture_emoticons))