Looking like an extended tent hiding on a hill in Henderson is the Henderson Pavilion, which is a great outdoor venue for concerts and theater.
Henderson Pavilion hosts the Henderson Symphony Orchestra, various musical acts, and the occasional theater production. The stage is set underground and you walk down concrete stairs to find a seat once you enter the place (or you can use the elevator). The acoustics are excellent.
One of the things that makes it such a great venue is the grassy area towards the back. If you're coming with children that want to run around or if you prefer to lay out in the grass, you can sit out on the lawn and still hear the music. It's a great music venue.