Speaking of the Calendar module, we have some problems with cyclic refs in it. It's very cumbersome having to destruct all the Calendar objects explicitly to avoid that, so it'd be nice to make it strictly acyclic. Could you perhaps give some pointers where to look for that sort of thing?
I think time ranges and possibly enumerating time periods (e.g. getting an array of the Days in a Week) are involved, but I'm not sure (I mostly see the Calendar garbage turning up in memory statistics - I'm very hazy on what the code that generates it really does).
Any hints would be appreciated.