Via a Jon Udell post I came upon this monster perl script by Jamie Zawinski. One of the authors of the original Netscape Navigator and therefore now a gentleman programmer and nightclub owner. The script generates the event calendar for Zawinskis club - and does so by doing everything itself withing wimping out and installing stuff from CPAN. It' all there: HTML generation, HTML parsing and cleaning, calendar and event logic including leap year calculators, tons of date parsing (which is what brought Udell to the script)
The cost: It's 6500 lines long.