Arguably the center of Utah extreme sports activities is the south western township of Moab.  Thanks to the Colorado Plateau up lift and then years of wind and water sculpting the sandstone layers, it has left an area of Canyons, Arches, Cliffs and general mayhem.  2 of Utah's best National Parks can be found here; Arches and Canyonlands.  Arches has over 2000 of these natural phenomenons scattered through the Park, of which only about 14 are readily accessible to the public.  The others are all hidden in and about the cracked slickrock surface, down in steep gullies and really aren't easy to get to for the everyday person.  You really have to be rather sick and twisted, or a daredevil, to try and get into some of those places.  There is a 11 km walk that takes you to some of the best arches they have, notably Double Arch which, as the name suggests, is a double arch, one on top of the other.  How this happens, I don't know, but nature can sure do some weird shit sometimes.  The slickrock that this rock is called is just that, slick.  On the walk we took the harder way, a primitive route that you tried to follow that actually went up and over and down this slickrock and several times you did need to slide down the rock to continue, or walk along a 'edge' with a 10m drop praying that didn't 'slide' here.  Truth is I don't know how you could have gone along this path the other way as it felt impossible to get up some of these 'slides' that we did.  Kudos to whoever made it that way.  Unfortunately the most famous arch, Delicate Arch, was closed due to a previous thunderstorm that washed away part of the road.  It's a pity for us because it looks like an amazing thing when I have seen it in photo's before.  Oh well, stiff shit, next time maybe.
Canyonlands is another American National Park that can give thanks to the Colorado River.  Not as big, deep or wide as the more famous Grand Canyon, it is still impressive to stand on the edge of the escarpment and gaze in wonder at the forces that could create such a massive canyon.  With the sun behind us highlighting the canyon walls and the snow covered La Sal Mountains behind that, you could be forgiven for thinking that is was the best view in the world.  It was just peaceful and a 'worry forgetting' moment.  Many movies have been made down in and around Moab including 127 Hours, the story about Aaron Rolston, a rock climber who went off on his own one day and got trapped in a chasm when a boulder dislodged and pinned his arm.  His solution; break the arm and then cut it off.  It's hard to believe someone being that 'stuck' but even looking from the main roads it's plain to see someone easily getting lost in all canyons and chasms scattered everywhere.  Audrey and I always stuck to the main paths, I like my arms ...
The town of Moab itself looks like it caters for every possible extreme sport you can think of especially if it's got an engine.  Every second shop had Buggies or Jeeps for hire, every fourth one was mountain bike hire and then every other space was a restaurant.  Either side of town was where you could find the RV Parks and Hotels and then the people lived on the streets both side of the Main.  I think that during summer this would be the place to be, activities everywhere.  We ended up staying 4 nights in Moab, we'd been flat out for the first 10 days, doing a lot of driving, and it was time just to have a few slow days off the road.  This was a great location.