I ran my first parkrun today, at the invitation of my friend Paul. Every Saturday up to a couple of hundred people do a brisk 5km run in Richmond Park (there are many locations - check this page for one near you).
It was a fun race in a beautiful park. Organisation is handled entirely by volunteers who are plainly well practiced - things ran without a hitch today. It's also entirely free - and there are t-shirts when you complete multiple races (10 for juniors, 50, 100 and 250). There were a few people with 100 club shirts on today.
Paul was way quicker than I was, so now I have a target to beat. I completed the course in 23:35, Paul was about 90 seconds quicker. From the graph below, you'll see that I'm very much a downhill runner.
Paul is looking to organise a parkrun in Battersea Park (which would have two benefits for me - it's nearer and much flatter) - so if that's something that would interest you, get in touch with me and I'll connect you.