1. Webshots - it has a basic free version, and it includes a wallpaper and a calendar. It also has a premium version, but it costs money.
2. Rainlendar (my personal favorite) - a small calendar that's tranparent on the desktop. It includes scedualed events, a 'to-do' list, syncronization with outlook and all kind of plug-ins. Very effective,low CPU usege, really easy to use, and absoulutely FREE.