Would you like weather forecasts on your calendar? There is an add-in that can put weather forecasts on the calendar. Infuser works in all versions of Outlook (and Lotus Notes). Go to http://www.infuzer.com/IDC/features/index.jsp to learn more and download it.

If you use Outlook 2007, you can subscribe to an Internet weather calendar. I kind of like the calendar at http://www.smashin.com/weather/  - it uses webding icons in the subject to mark sunny & cloudy days.

Weather Underground ( http://www.wunderground.com/ ) offers ical (and RSS feed). Enter your zip code, then click the ical link at top of the page (just below the banner ad and to the right). If you need weather for more than one location, both of these sites support multiple calendars.