Kleine Scheidegg -hotel and train station for highest railway in Europe.
The Jungfraujoch is the endpoint of the highest railway in Europe, at the peak of the Jungfrau mountain. From here you can go sledding on the glacier, walk through an ice palace, or shop & dine in the train station complex built right into the side of the mountain. Along the way there, the train stops at viewstations inside the mountain and you can look out onto the glaciers.
Schilthorn is the cheaper alternative to the Jungfraujoch, offers the same view but from the other side of the valley & minus the glacier. On the mountain peak is a revolving restaurant called the Piz Gloria, where the 007 flick On Her Majesty's Secret Service was shot.
The Truemmelbach Waterfalls are not very impressive as waterfalls, but beautifully located in the mountains. The Truemmelbach Fall itself is not to be missed. The sole outlet for glacial melt in the area, it cuts through the *inside* of the mountain and can be accessed on foot via a lift. It costs money to view, but is well worth it. The power of the moving water is intense in such close quarters. You can reach this by bus.
The Aare Gorge is a 1.4km long, 180m deep gorge of the river Aare, accessible by tunnels and paths. It's west entrance is next to the village Meiringen. The highlights of the path are closer to the west entrance, so you might want to enter at the east entrance and work your way down with the river.
The Oeschinen Lake is a beautiful mountain lake next to the village Kandersteg. It is included in the UNESCO world heritage list. You can reach it by foot from Kanderstag in about an hour. Alternatively, there exists a cable car that takes you up. Next to the lake is a toboggan run and two restaurants. You can also do some boating on the lake or have a picnic on the shore. If you like hiking, you can continue up the Bluemlisalp-mountain.
This is probably the finest area of the Swiss Alps. Most people will come into Interlaken, sitting between two lakes, the Thunersee & the Brienzersee. From Interlaken, twin valleys go to either the resort town of Grindelwald, or the Lauterbrunnen, which has cable car connections to several stunningly located and isolated towns. Several glaciers are in this area.
The Brienzer Rothornbahn train runs up the mountain overlooking Brienz, providing fabulous views of the Brienzersee. It is also the last mountain railway in Switzerland to exclusively use steam engines (although they also have one diesel unit).
Lake Cruises The clarity of the blue water and stunning mountain scenery make cruising on either the Thunersee or Brienzersee a great option
Cable cars Another great thing to do is ride the many cable cars that criss-cross the valleys, providing awesome vantage points
Biking Rent a bike in Murren, ride down the valley, and ride the cable car back up
Hiking There are countless great options, one of the best being hiking a mountain ridge parallel to the Brienzersee