Mountain Biking in Denver?

Yesterday I stayed in Denver (actually, Littleton, same idea, different suburb) with my friend Will's mom. I based out of her home for a sweet mountain bike ride.
Of course the first few miles had nothing to do with mountain biking. I was able to hop on the local commuter trail and ride my way to Chatfield State Park, no roads involved. From there I hopped on Deer Creek Road, which must be the place to climb for all the roadies. They were all out in full kit, looking like a flock of hummingbirds in their bright, matched jerseys and shorts. yours truly earned a few odd looks for my bike, but most were friendly and waved as they went by.
My original goal was Deer Creek Canyon Park, and though I was able to get in a little bit of righteous singletrack switchbacks in, most of the trails were snowed in. So I popped across the valley into South Valley Park. There I rode under the watchful eye of the Lockheed Martin security guard (who was very helpful in pointing the way, I might add), on some of the most aesthetic singletrack I've seen in the Front Range. The trail itself was narrow hardpack slicing through a beautiful open field on a plateau from which the mountains sprouted sharply upward. I went over to the more widely travelled parts of the park, until I ran across a donkey, and decided to go back to my high plateau. I rode the same trail in reverse and loved every minute of it the second time around as well.
After the high point (both literally and figuratively) I headed back down Deer Creek Canyon road, where I hopped on the wheels of a group of roadies. Free ride! I sat and spun in their slipstream, a mountain biker keeping time with roadies, much to their dismay. Hah! And they didn't even get to hit up any sweet trails. Sucks to be them.
And so I made my way back, past the spillway into Chatfield Lake, under Highway 470, over the pedestrian bridge for Mineral, through the RTD station, and finally past the dirt jumps back to home base.
Grand total: 3:58 minutes of riding, I have no idea how many miles, and one sore butt.