We are having weekly one hour compos in the channel #modulez on irc.esper.net. The general rules of a one hour compo are explained
here.
The compos are held every Sunday 19:00 UTC during DST (that's 21:00 CEST) and 20:00 UTC otherwise (21:00 CET).
There are currently also daily one hour compos at #mod_shrine (also on irc.esper.net) following the same set of rules.