I cannot tell you if Time & Chaos is a good shared calendaring solution or not as I've not tried it (yet), but if you applied time and chaos to a date, I'm sure the results would be interesting to say the least. Hmmmmm....

BTW, there are a few other calendaring solutions out there, but most are limited to single user, non-shared environments. Time & Chaos does allow sharing of calendars, but it looks like it is limited to 'doze and PDAs.