I posted the same question on glocals. I got the below reply. The other thing I thought of was simply calling the indoor ice rinks and asking them if they have leagues that play in the spring/summer. The research if for my husband who won't get here until next month so I haven't called the rinks yet. But you can google ice rinks in geneva and they'll pop up and you can call. There are about 4 of them.

Hi,

I play for CERN ice-hockey : http://club-ice-hockey.web.cern.ch/club-ice-hockey/

Anyone can subscribe and join, most of the players are foreigners, so we speak in English. It's real fun, but we don't play in a league, just do some trainings.

The season will start again in October as the rinks are closing at the end of March.