Last November I paced a friend (a recreational runner in his mid-50s) who wanted to run 10 min/mi in the local Turkey Trot 10K. I was still in recovery mode after the NYC marathon, so wasn't interested in really racing.
I ended up having a blast. It was fun to feel completely relaxed and unstressed at the start, knowing that this wasn't going to hurt, not even a little bit. It was fun to take in all the goofy costumes. It was fun to wave and holler at the lead runners when they headed back our way.
And though my ability to pace *myself* in races is pretty weak, we finished in exactly our goal time, which made me feel I'd accomplished something.
So, yeah, even though I'm usually out to be as competitive as I can (given my advanced age and modest ability), I'd do something like that again. I don't see myself running slow on my own, though - I draw the line there.