On 13's theme, you could take up yoyo? My teenage boys are way into it, planning on going to the regionals in Seattle in a few weeks, as spectators. Although, one of the boys nailed his his brow with his aluminum yoyo, split it right open, probably a liitle more dangerous than the competitive knitting. I try to look cool with my yoyo (One Drop 54 mm), not very good, its about the exact size of my acetabular cup, though. Cool, huh?
Anyway, at 5 months I went downhill skiing, and all was fine other than I got the squeak at the end of the day. I suppose I could have had an accident and busted things up, but that didn't happen. I think it's ok if you moderate. I have heard of surgeons give the "all clear" at 6 months and there are others who are adamant about waiting the full year before any running, impact, or hard-hitting types of activities are done. Best to probably do what your particular surgeon says.
Now I want to play hockey.