BuddyPress.org

What I wonder as I look at this is wouldn’t it be easier to take a robust plugin for wordpress and make it work well with MU/Buddypress. That seems like a better place to start, especially if the original author can point you to the right places in the code.

I mean the functionality of a good calendar plugin should be pretty well understood at this point. Priorities and roadmap might be trickier, but the end goal should exist in the PHP if not WordPress world.

This raises my recurring question of how hard is it to turn a quality PHP script into a good plugin.