Ya know, I never thought of that, but its not a bad idea (recording a live act to get an "in" with them).
Pick a place that plays the type of music you play, and offer to do a night of recording for em for free, and as a trade, perhaps have you open for em the next time, if they like the results of the recording.
Of course, this depends on your equipment list. When I was a senior in high school, beyond my drums and electric bass, I had a 7-year old Pentium 1 desktop and no recording system beyond a Portastudio cassette 4-tracker. Things have changed since I went to college, graduated and got a job... bought a decent PA system (nothin fancy - a sub, a couple woofer cabs, some power amps), and I can integrate my DAT recorders and pre's into the PA system for seemless recording of the shows I play.
Never thought to offer that whole packaged service for free to somebody (which would of course include mixing the stuff yourself as well), and then giving them the final results, to trade for a chance to play.
Its a shot in the dark, since the quality of the recording is up in the air to an extent, and you won't know if they are pleased with the results until afterward, but it would give ya good recording practice in any event. Again, this is if you have the equipment to do so, and many people do not (and understandably so, this shit costs a pretty penny to get and maintain)...