Switzerland is obviously super popular for skiing, paragliding, and skydiving. The main reason that I wanted to go was to sky dive, which we did in Interlaken. It is incredibly expensive, but my honest advice is to not let the price divert you. My skydiving experience was absolutely worth every cent, and I would pay the same amount tomorrow if I had the opportunity to do it again! I also know people who skiied and paraglided, who also reported that it is efinitely worth the money that you spend. Do the crazy things- when will you have the opportunity again to jump out of a plane out of the swiss alps?
If you do go to Interlaken, take a chocolate making class. You get to spend time with a Swiss chocolatier master chef, and that is definitely a once in a lifetime opportunity.
The only tip I have for Switzerland is that you need to mentally prepare yourself financially. Switzerland is by far the most expensive country in Europe. An average meal you will be spending around $30 per person. It will be the best experience of your life, but make sure that your wallet is ready!
Switzerland pretty much has every single kind of food that you can dream of, but you definitely need to try the Schnitzel and the Raclette. You will not be disappointed eating both of these at every meal.