I've lead up to a sprint thinking my rear derailler was out of allignment. I went into the sprint and pounded the gears, as is normal four our group at that point, then pulled off to the regroup lot. My chain sounded like hell at that point and I finally looked down to realize that things didn't look right. Fortunately, one of the local shop owners was on my wheel and saw that my chain was about to self destruct. He had to pull three links, held in by pins which he barely had to touch to get to fall out.

In the end, I paid for his beer at the end of the night (didn't charge for labor), bought a new chain from him, and a new chain tool to carry with me since mine turned out to be a piece.

I learned that night, the importance of proper shifting, and of letting off the gears when I do so. I'll readily say I'm still learning since I've only recently crossed my first 1K mile mark since about March. But in that amount of time, I managed to shred a brand new chain. Don't do that.

If that chain had let go in the sprint, I would have been eaing the pavement at 35mph, and been having a really ****ty night. Mind your chain if you're going to mash the gears, and pay attention to wear when it shows up.