Marred by Adam Shankman’s uninspired direction (Hairspray fit more like a comfy housecoat) and mainly lifeless performances, Rock of Ages (C-) is a tedious karaoke with the stars. It’s a musical with poorly performed ’80s songs and choreography, and only about five jokes actually land. Tom Cruise is pretty good as Lestat, except that’s not who he’s supposed to be playing. The young leads are lost in the tacky bombast.