Anyone seeking a four-day crash course in Brooklyn Rock (both from BK and of it, I guess) is hereby advised to delved deep into the Northside Festival, which packs hundreds of bands into multiple venues across the sweetest of boroughs, starting tonight with a raft of shows, led perhaps by the triumphant (?) return of Wavves at the Knitting Factory. Plenty of rad stuff to mess with — those day/night shows Saturday and Sunday at Newton Barge Park (including Titus Andronicus, Liars, Elvis Perkins, and Les Savy Fav) look particularly splendid. I asked L big-shot Mike Conklin for dark horses: He suggests North Highlands, Gabriel Birnbaum, and Shark? That’s Shark + question mark. We’ll see you there — try and act like you knew about all these bands already.