Some teachers asked me to join them in a table tennis match after school. I must be worse than I thought because the P.E. teacher spent about 15-20 minutes coaching me before and after we played! Nevertheless, I had a really good time, even though I couldn't play at the level everyone else could.
I remember playing with the kids quite a bit after school sometimes in Japan, but I'd never received any proper coaching or instruction. The guy gave me some great tips and I think I improved more in an hour than I had in months (not that I've played in months).