"Limped home" once when the front brake caliper bolt came out leaving my front brakes dangling in the wind (or rattling off the spokes if you were not careful). I kind of carried it home in my left hand while riding carefully. Around 12 miles - could have been worse I guess.
I also once took off a cycling jacket and wrapped it around my waist. Not long after that one of the arms (or something) came loose and it got sucked by my rear wheel into the rear brake calipers. I was going downhill at maybe 30 mph at the time. It kind of shredded the tire and was so tightly stuck between the wheel and calipers that I could not get the wheel off (not that it would have helped without a spare tire). Had to flag a ride. The first guy that stopped was in a really small car with no room for the bike, so I hid the bike in some bushes and as quick as I could drove back to get it. I got lucky - it was still there.
dave