FlexTime 1.0 has just been released and time obsessed Mac users rejoice! What is FlexTime? Some might call it a timer, but it is a very advanced timer. You can build 'routines' based on timed intervals, which in turn can cue you with a number of different cues (i.e. it can play a sound, run a script). This is a very slick app that some people will find extremely useful.
FlexTime 1.0 will run you $18.95 and requires 10.4. There is a 30 day demo available.