The semantics of event schedules

I seem to be stuck in survey mode tonight - and ran across this groovy little lightweight event scheduler from the Czech Republic, EasyTime. And really, event scheduling is pretty ramified if you start really thinking about it. When I was working out the basic feature list for the wftk, I sort of intuited that an event scheduler would have to be part of it - but seriously, you could do worse than looking at the feature list of EasyTime.