Not a riding achievement.

But I've had a bike for 5 years and just changed my first tire. Got to the parking lot to go for a ride, pulled the bike out, and the back (oh yes, I had to start with the hard one) tire was completely flat. I suppose this was inevitably what I deserved for going to ride knowing that I had no spare tubes or air source with me.

The only bad part was inflating the tire. I have presta-to-schrader adapters on my other bike and I thought, oh, let's make this easy and use those! Only they unscrew the inner part of the valve stem on these tubes when you take them off, and then ALL of the air goes out, immediately. I found this out after I inflated the tire the first time, and it took me about 20 minutes to figure out how to make my floor pump shove air into presta valves.

All fixed. Now it's too dark to ride, but at least the bike is ready for Sunday!