consider myself straight. Never did anything with another guy, not even masturbate. I do though remember for a short period of time becoming aroused by and masturbating to certain aspects of my best male friends when I was just starting into puberty.
Update: Over the last year or so I've become increasingly bi-curious. Especially after another Bi-guy PM'd me from another forum I'm active on about having some masturbating fun together. I've had some incredibly strong fantasies about this and have been wavering back and forth about following through with it. I think it would be an incredibly hot time, just not sure if I'd feel guilty about it afterwards.