LONDON - I went to cycling Friday and found out about the Keirin.

That's OK, I didn't know what it was, either.

I'll deal with this more in depth in Saturday's column in the Sun-Times, but here are the basics: A pacer on a motorized bicycle starts out at about 18 m.p.h. for a few laps, then increases his speed gradually until the racers are going about 30 m.p.h. for an extended period. After that, he veers off and lets the riders make a mad sprint over the last 700 meters to the finish line.

It's insane.

My clumsy photography skills don't do this justice, but check out the dude who was pacing the pack in a heat Friday. He looked like he was about 70 and headed for the grocery store: