Need suggestions for a calander program (Free and not Outlook)

[MrBond]

I've decided it'd be nice to have some sort of calander with all my appointments and stuff on it to keep me reminded. I like outlooks calander, but I'd rather not use outlook's mail (I can't get it to filter as well as outlook express). I suppose I could just use the calander and not the mail, but I'd rather just have one application for the calander and one for the mail.