[quote="Mike"]I said violin, but really I play the viola, which is slightly different

I'd put up "vocals" also, though it's not really an instrument lol[/quote]
Anything that can produce a noise is counted as an instument. Like pots and pans aren't really a standard drumset, but you can make a drumset out of them. Vocals are an instrument.
I put down Guitar (Which is my normal instrument, I play Electric, Bass, I bet I could play accoustic too), Vocals/Singing, If I went up to a piano I could play it, but I don't usually play piano. Although I haven't been a musician for long, I've been quite interested in learning the guitar, since it's such a great instrument, and most music you hear has guitar in it.
I started my own band, which is soon going to be a sideproject, once I find a band to join.