Switzerland is a beautiful place. As you probably know, the Swiss are famous for their pocket knives, as well as their chocolate. However, the biggest attraction is the landscape. There is a lot to do from skiing, to hang-gliding.
Glacier Express should at least be looking into. Its one of the best train rides in the entire world! It goes from St. Moritz to Zermatt. There are stops at Davos, Chur, Brig, and Visp. It's a 7.5 hour ride. This is best done during the winter.
There is a lot of Hiking and trekking. It's very popular in Switzerland. Its good to get the best sceneries of mountains. Plus it's great exercise.