Don't feel like making a web page to keep your stats? Here's another way. Keep the information in a text file, one line per show. Enter shows in the format month/day/year (e.g. 12/31/99). Cut and paste it into this text box. Stats will be computed with that.
If you want to compute the Not Played list and the 50% club starting with your first year of seeing Phish, instead of their whole career, include a line saying "First Year"
Tired of the old 50% club? Type in a line saying "club-40" and you'll have the 40% club. Change that number to anything between 1 and 99.