I was searching for a really good Joomla 1.5 calendar. I started using the com_events_1.5.0alpha2 build and I originally scrapped it, because it didn't create the db correctly upon install. I then noticed the two devel links on the left hand side that correct the db problem.
After that it works awesome. I was able to change the output of the latest mod and I was able to do everything that it advertised. I would say that this is the best Calendar component out there for Joomla 1.5.