There are some great new features with Calendars in 2010; specifically I am referring to the overlay feature. This feature basically allows you to add additional calendar views to your view and display the entries with a specific color. Here are some screenshots of the feature. It looks like the limit is 10 calendars and you can add either SharePoint or Exchange calendars. I didn't have easy access to exchange, so I just tested the SharePoint calendars. I added 2 new overlays to my view – another calendar (Calendar 2) and a Tasks Lists Calendar View (Tasks). This shows that any list that has a calendar view can be displayed in the overlay.