There's a 30 day evaluation which I'm using at present. I've found it excellent.
It's a seperate application but you can configure it in your Joomla databse. Joomla integration is excellent. The Joomla Studio is very powerful and essentially lets you design your own Joomla modules.
A very powerful, flexible utility that integrates well with Joomla but requires a bit of a learning curve. read the docs! Will be buying.
Man I wish this was open source...I think Joomla really lacks a good calendar component that integrates really well with many options. I think it would be nice to have a calendar in the "core" install.