As an Offspring fan, sure this sounds like an awesome idea. However, I can't imagine your average bar scene being thirsty for an entire set of Offspring covers. Most people won't know a lot of the songs, and bars (generally) look for bands to play a variety of well known songs from many bands. Being in an Offspring cover band could be a lot of fun since you are playing great songs from a band you love, however I'm not so sure it's the best idea if you are actually looking for gigs.