It looks like the band is getting ready for the Fiesta Bowl. Even though they're performing the instrumental version of Star Spangled Banner, the entire band is involved with it (which means Brad Delp and Fran Cosmo are participating despite the fact that they won't be singing).

The whole band has spent the last few days rehearsing, and will continue to do so until the event (they'll even be having a dress rehearsal, from what I hear).