Dang... my calendar from last month just upped and disappeared. I've tried re-syncing it with Outlook, but to no avail. (All my events/meetings show up in Outlook, but not on the Crackberry.)

Any ideas for a fairly new user?

Older calendar events are automatically deleted...

However, you can reconfigure BlackBerry Desktop to avoid automatically deleting past calendar events. Once this is done, you can re-synchronize again and if they are still in Outlook, they will now show up on your BlackBerry.

Also, on an OS4 BlackBerry, there's the "Keep Appointments" settings in:
Calendar -> Click trackwheel -> Options