Love to do it. Did a big half marathon (Reading) a lot of years back and it's a hell of a buzz running in such a big race with so many people watching. There were about 12,000 in it, I came 4,485th and was crippled for days. Had to crawl into the pub after, jumped out of my mates car to get the beers in (was close to closing on a Sunday lunchtime) and my legs gave way....couldn't get up .