XASON  I'm having similar trouble. Mine froze on the seventh. The icon for being closed is stuck on seven, and the icon for open still updates but cannot be changed. I got rid of everything I could find, but it still updates! I emailed the developer as well. Hopefully we'll get this fixed soon.  
(Version 1.4)

XASON  Great work. The new version has just about everything anyone has mentioned, and it works great. A couple more suggestions - It would be nice to have the month, not just the date as an option when iCal is closed. Also, for those that don't log in and out every day, a preset to update without having to make your own iCal alarm would be a lot easier. I'm definitely upping my previous review  
(Version 1.3)

XASON  Great. The new version does close iCal when it's done like it should. That different font is starting to bug me though, I think it really should look the same whether open or closed  
(Version 1.2)

XASON  Still some bugs, but exactly what I've been looking for, and the developer is making quick progress. Like others, I'd really like for it to run automatically in the background and change the icon without opening iCal. The option to close iCal still doesn't work for me on my PowerPC, so I had to create an Automator workflow that opens this program and then closes iCal. I'll keep checking back - keep up the good work.

Also, is it just my screen, or are the fonts for the number different for the open and closed icons? More options would be great, like icons that still have the month when closed or that don't have any number when closed.  
(Version 1.2)