Ka (2005)

Normally we'd be dripping sarcasm if we called a show ''a brilliant triumph of hydraulics'' — but this time we mean it. Not that the human element is exactly missing in Cirque du Soleil's fourth acrobat-filled Vegas show, Kà. But this one has as its principal ''stage'' an enormous, seemingly free-floating slab of steel. In one scene, it's a beach, with sand and playful giant crab-people; then the stage tips over, that sand slides off, and suddenly it's a mountain, with pegs popping out so the cast can enact an alpine chase scene. Ignore the fairy-tale narrative: Here, all the world's a totally awesome stage, and the play's not the thing. (877-880-0880) A-