If you purchase a box of Girl Scout Cookies from the daughter of one of your colleagues, they contain no calories. Girl Scout Cookies from all other sources do contain calories.
I admit that I went for one of the (relatively) more ascetic options: sugar-free chocolate chip. Yeah, yeah, I know. Not that I don't love Thin Mints and Tagalongs.
(Ex-Girl Scout: made it to Cadets. I think I've got my Brownie pin hanging around somewhere.)