Now Available at David.Blackledge.com:
Download the zip, unpack it, and run the .bat file... then the application is available from your TiVo DVRs if you have home network applications enabled.
Read the README to configure it to view your ical calendar files or URLs (e.g. Google Calendar)
It's not as pretty as much of the applications you see for TiVo... I just don't have much time to spend on this hobby, so I don't take time to refine things. It's very functional, though, and I look at it almost every day since I keep my main calendar on Google.
Future plans when I find the time: cache/prefetch the calendars so it comes up faster; display improvements; fix the page up/page down (right now it's completely broken... don't use it)
Let me know if you have any questions or comments.