Around here we have two kinds of snowmobiles.
We have trail-riding units that are used to travel along snow-covered fire-roads, across open fields and used to pull winter-camping gear on skid-trailers (imagine removing the wheels from a quad-trailer and replacing the wheels with skis). These snowmobiles are low-power, torque-based units that are not designed with "thrill" in mind, but, with utility. That doesn't mean that they can't be fun as well.
Some current options on utility-style snowmobiles can be found here:
Utility Snowmobiles: Utility Snowmobile Reviews, Videos, and Pictures
Then, we have the thrill-seekers.
One guy I know has a 6-foot track that extends way beyond the back of the actual machine (
as shown on this link) and is running close to 700hp under the hood. He does "powder-surfing" and "vertical-climbs" where he might ride an avalanche-wave on his snowmobile or power against an avalanche to try to reach the top of a mountain.