Geiranger is a village in Møre og Romsdal. The Geirangerfjord is one of the most beautiful mainland fjords. In a rating of UNESCO world heritage sites, Geiranger (along with Nærøyfjord in Sogn og Fjordane) obtained top score in a survey conducted by National Geographic.
No need to use the tour boats. You can see just as much from the Hellesylt ferry with commentary in German and English as well as Norwegian - from a comfortable lounge with a good snackbar.
The steep-sided fjord with its waterfalls, including the Bridal Veil and the Suitor.
Kayaks can be rented by the waterfront (although, as with anything in Norway, it isn't cheap), either by the hour or for a whole day. Kayaking down the fjord is a very enjoyable experience; it offers spectacular views of waterfalls, mountains, and even, occasionally, dolphins.
The "Sky-to-Fjord" trip, run out of one of the small gift shops by the ferry dock (easily identifiable by its green roof), is a spectacular 17 km bike trip from the top of the mountain (high enough to still have snow in August!) back down to the gift shop. The trip includes van transportation to the top of the mountain and bike rental. You can go at your own pace as long as you return your bike to the gift shop by the end of the day. Take your time, as the spectacular views can make for worthy detours!