If you want to ski down the mountainside, you'll need to reach the top of it first. Jump on Monte Piz Ski Lift and enjoy the ride up.
You'll have no end of sightseeing choices when staying in Castelrotto. Monte Piz Ski Lift is a great place to start here, but there are loads of other interesting sights to check out. Seis-Seiser Alm Gondola, Seceda Ski Area, and Furnes-Seceda Cable Car are close to the mountainside transportation system and and will cap off your day nicely.