Between Script-Fu and the odd Python-Fu plugin, I clearly can't stop coding even when I'm meant to be relaxing - so my "downtime" project is yet more Python, just pointed at something totally different: rating tennis players.

It reads historical ATP and WTA results and gives every player a single strength number, then adjusts it after each match - an Elo-style approach, the same idea behind chess ratings. It started as a tiny script and slowly grew into a little engine: surface adjustments (clay vs grass changes a lot), decay for players who go inactive, and sane handling of mid-match retirements. As usual the data cleaning eats most of the time - public match records are surprisingly messy.

Figured this crowd would get the "I relax by writing more code" thing. Does anyone here keep a coding hobby that has nothing to do with images? And if you've ever messed with rating systems (Elo, Glicko, TrueSkill), how did you handle volatility for players with very few matches? That part I keep rewriting.