dashndash, depending on the reason for your ban, you can fill out a online appeal. I know of three people that this has worked for and it's worth a shot depending on the reason.
go*ogle.com/support/ads*ense/bin/request.py?contact=inv*alid_clicks_ap*peal
If you have been banned many times from the big G, obviously this won't work.
Short of that, I'd buy a new domain and register it under proxy. Throw wordpress on it and make some content by rewriting some articles or whatever. I've done this in the past and it works every time.
A bit more info on the site your trying to get approved could help us figure out what's the best course of action.