Continuity mistake: When the camera is focusing on the pool at the hotel it slowly moves up and then we see Ryan and Seth walking down some stairs (in the upper left hand corner). We can see Ryan swinging his arms and he's not holding a drink, but in the next shot he's holding a drink.
Visible crew/equipment: When the pimp and the girls start bowling and Ryan and Seth join Summer on the couch, there's a huge bobbing boom mix hanging centre screen.
Answer: Hallelujah by Jeff Buckley.
Bobbert