CalendarPane is a library for displaying either a single month calendar or a multi-month calendar. The calendar is interactive and the behavior can easily by modified without changing the library, so that different calendar panes can have very different behaviors within one project. Here are screen shots of a few calendar panes created with this library:

Vertical PaneSingle PaneHorizontal Pane

You can download the CalendarPane archive here, which contains the library as well as detailed documentation and instructions.