I've always been a fan of the Office Online site.  It's great for when you need a last minute template or a piece of clipart to make that PowerPoint or Word document a little more exciting...  and now it even has a link to our Office Live site!

Well now, it's been brought up-to-date with the 2007 Office system look and feel - with a ribbon!

As Darren mentions, you can even publish your calendar so other's can see it...