The Rialto Casper is a downtown theatre with the kind of marquee that gives a Western city centre a bit of nighttime presence. It began as a movie house and now functions as a film, music, and event venue, keeping some entertainment life in the older commercial blocks.
Check the schedule rather than treating it as a daytime attraction. Even from outside, it is a useful stop on a downtown walk with the historic district, bars, and civic buildings, especially if you like old theatres that have survived the mall-and-multiplex era.