The most obvious thing would be for one of the bands to arrive early and perform an acoustic set. In that case, my money would be on Redemption.
Less obvious, and probably a lot cooler, would be Urban debuting his solo material.
Even less likely, and even cooler, would be our good friends Dreamscape, so eager to play for us that they'll do the pre-pre-party.
Least likely of all would be a full performance by an established international act. But that would be the kind of thing Glenn could pull off. There are a few international acts that will be running around the country at that time(Kamelot, Edguy). The Vinyl Club is the same as any of the other clubs they'll be playing. Might as well add a date where you're sure to sell out and probably have more fun after the show as well.