We joined Joel, et al, for his
Heavy Metal ride on the tandem. About halfway through, while standing and climbing a hill, we heard a kind of "kapow!" sound and the chain fell off the middle ring onto the smaller ring and off (in less time than it took to read that). Turns out we lost 4 of our 5 bolts.
We limped a couple miles to the Trailhead Coffee and Bike Shop, where the proprietor fixed us up so we could enjoy a fast, smooth descent down Folsom-Auburn Rd.
Fun ride with good people. I hope we can do it again soon.