If you're in San Francisco this coming Sunday (yes, Easter?), I highly recommend this racing event which lets you break out the non-rubber wheels for an afternoon:

http://www.jonbrumit.com/byobw.html (hit mute on your computer before visiting link!)

I did it last year (hey, my icon!), and had an absolute blast! Even if you feel like avoiding road rash and don't participate, it's a bundle of laughs to be a spectator, too!

-- gnat!