You know you're ______ when...

Last night I was so bored that I was literally watching a History Channel documentary on concrete. I didn't even know there was such a documentary; I thought it might be one of those things people hyperbolize about to illustrate how dull educational TV is. But no, there really is an hour-long program on it. And I suppose it's even moderately interesting, if you like engineering and Building Stuff; but after about half an hour I decided I was being just too pathetic and went upstairs to do the New York Times Sunday crossword on my computer. Which is just as nerdy, I guess; but at least it's not the punchline to a "you know you're _____ when..." joke.