Music festivals are mostly about wading through a sea of mediocrity to discover the one or three new acts who qualify as Killer on the basis of their charisma, or their tightness, or the pure strength of their sound . But, it's just as much about supporting friends and the familiar, which is what brings me to tonight's New Amsterdam showcase at Glasslands Gallery. Surely one of the most unusual showcases this CMJ, I arrive just in time to catch the tail end of So Percussion performing Steve Reich's "Drumming", to a half-empty room of curious onlookers and awkward hangers-on. (Glasslands is way off the beaten path, on a remote stretch of Kent Ave near the water.) On now is itsnotyouitsme, Caleb and Grey's plugged-in drone project, which fits a fair bit better. After them is something called Beyondo(?), which I doubt I'll still be around for.