Colorado Senate Bill 36 was written to acknowledge the inherent risks of mountain biking, and to limit lawsuits against property owners, equipment renters, etc. over injuries sustained during the activity.
The bill died tonight, having never made it out of committee.
What I find interesting about this bill is that it was a wholly Republican endeavor from start to finish.  It was sponsored by a Republican, and the vote on it was strictly down party lines: Republicans for, Democrats against.
This speaks to a suspicion that I have long had. Mountain biking is largely a Republican activity, because Republicans insist on seeing bikes as toys.
One blogger recently wrote about how in her community bikes were considered suitable for kids to play with, but were completely inappropriate for an adult to ride.
There's some kind of mental trigger that produces this mindset, and I don't know what it is. But I think that whatever it is, it's the same thing that causes motorists to get angry at cyclists for being in the road. The other side of the "They think they're entitled to the road" coin has to be "I believe they have no entitlement," which means that to the coin flipper, the cyclist is a kid playing at grown-up games and should be riding bikes on the sidewalk. Or playing hop-scotch in the alley. Or kicking a tin can in a dirt field. The idea that a bike might be used for grown-up reasons—going to work, grocery shopping—is not reasonable, nor even plausible, to this person.
(This coin-flipper is the same person who honked at me twice this week for not riding in the bike lane when it was full of snow and slush and ice and muck.)
To this person, the idea of spending Department Of Transportation money in multi-modal transportation is ridiculous. Because bikes are toys, and who walks anywhere?
"Bikes are toys" is the mantra that allows anti-bike people to embrace mountain biking. In this activity, bikes are safely confined to recreational use far away from cities and roads and traffic.
As proof, I submit the most—the only?—outspokenly anti-bike politician in Colorado, or anywhere else, Dan Maes.
From the transcript at grist.org:
The bike program in and of itself is fine. I'm a biker, I rode the seat off my mountain bike last year myself.So. Cycling in the city is a UN conspiracy to rob us of our freedoms. But cycling outside the city, in the mountains and in the woods, is peachy-keen and supports family values.
I am not against mountain biking. I find the idea of it appealing. I am simply interested in the apparent mental break that exists in people who are for it, but who are against cycling in the city and who are against infrastructure that supports it.
Because in one case, cyclists are simply kids playing with toys. And in the other, cyclists are humans, people who are just living their lives, doing their jobs, trying to live simply, and to simply live.
 One caveat from bicyclecolorado.org
This bill was conceived by past Senator Chris Romer after encountering many liability obstacles in trying to host a mountain bike event.Romer is a Democrat currently running for Mayor of Denver and who appears to be very fond of the cycling demographic.