Can't believe no one has mentioned Kountry Kart. It's been a while since I ate there, but they're open quite late for the after-theatre and bar crowd. GREAT onion rings. They're right next to the Flynn Theatre.
Nectar's on main street still serves late night food and probably will have a live band too. As far as quality of the food goes, I haven't eaten there in years; it used to be best eaten at the end of a long night and just before you walked up the hill toward campus.