I live near this little "city" thing that has a group that puts on all ages shows. Generally it's your usual acoustic guitar and high-school garage band stuff you would expect to see if you were around this area. After I did RPM Challenge 2009, a friend told me to sign up for a gig with this all ages group and after laughing it off with "yeah, would be fun," I eventually did.
I was in a library, I do not know why the library had a stage or a PA system, really weird, but that's where I was. About forty to fifty people were there, all to see the main act who was from another city over. I went after a one-man acoustic guitar thing and some horrendous death metal flailocolypse group who really sounded plain awful. Then I go up as horribly afraid as can be and began with what is now my usual stage-banter catch phrase "All you hipsters out there, go tell your friends you saw Beverage in concert, they'll think you're beyond awesome!" Maybe three laughs.
The music was okay, not my finest work, but the novelty of gameboy music always gets you through the first gig, somebody out there will enjoy it. Mostly people just stood there, a couple of kids moshed, and a homosexual couple ballroom danced and kissed a bunch. Seriously weird, but pretty entertaining nonetheless to look down from the stage and see those loons. I think that the audience really makes this sort of thing possible for newbies - if they like it, you have a good time. But much like Bit Shifter said above, I also stood shy of perfectly still and really only moved to piddle with the mixer and get my circuitbent garbage to behave.
After everything, the lead act asked me to come back in their set and do a little improv thing with them - I used an emulated version of Pixelh8's music tech pro I happened to have on my PSP. Real classy. I didn't know any music theory at all, the guitarist whispered to me what key we were in every now and again and I changed the key accordingly. I sounded awful and out of place, but they had so much fun that I got asked to do that again on the fourth of July at some bar.
tl:dr, rocky beginning, but in little towns like this, people can be accepting. I'd have changed things by having better music, but coming home after that first gig after getting applause and all of that junk was pretty great. Euphoric I think is how I described it at the time. Eh. Also, watch out for gay ballroom dancers - those guys were crazy.
