I just noted completing a sextuple double, by riding the Knoxville Double Century, but it was also my tenth ultra century this year (rides of more than 100 miles).  In the interest of keeping score:

Still, who's counting?  Okay, okay, maybe I am.  Hoping for some more of that metric magic :)

Actually I've been keeping score another way, too.  After each ultra century, I've fashioned a little sticker commemorating the ride.  This is what the top tube of my bike looks like now:

(ultra century stickers - click to enbiggen)

Pretty cool, eh?  I get a kick out of making a new sticker after each ride, and I like the admiring stares when I ride with my local club on weeknights (the Conejo Valley Cyclists). Yeah, I’m a bit of a ham, what can I say.