Unicycle rollers 20:00 
No, I'm not kidding. I was just going to see if I could get balanced at all in a doorway for long enough to have Nancy take a picture, and then photoshop it so that it looked like I was actually riding, so I could post it here as a prank. Didn't know if I'd even be able to get up onto the seat, because it seemed like, with the instabilities of the unicycle combined with those of the rollers, it might be like trying to stand on a ball that's on a sheet of wet ice. But I got seated okay, and when I pedaled, everything moved like it was supposed to, and I didn't have to cling to the doorway for dear life like I was expecting. In fact, I could ride just fiine with one hand on the doorframe to assist in balancing, and even more surprisingly, I could let go for several seconds at a time, and sometimes even felt like I was making stable corrections, not just "I haven't hit the floor yet". It would be a bit easier, I think, if the rollers had more of a load hooked up to them, because fore/aft stability is an issue, where sometimes I start tipping forward and can't pedal fast enough to correct. Managed to work up more of a sweat doing this than I would have expected.
Nancy arrived while I was riding, and all I could think of to say was, "This is so cool!".