I'm happy to announce the first fully functional release of time-recurrence: http://hackage.haskell.org/package/time-recurrence As of version 0.5.2, the library is now powerful enough to express all recurring dates which can be specified via the iCalendar RFC. An example: Generate the 15th and the 30th of the month, but only during the work week: > jan2011 = ptime "Sat, 01 Jan 2011 00:00:00 -0400" > jan2012 = ptime "Sun, 01 Jan 2012 00:00:00 -0400" > takeWhile (<= jan2012) $ recur monthly `starting` jan2011 $ > enumDays [15,30] >=> > filterWeekDays [Monday .. Friday] [2011-02-15 04:00:00 UTC ,2011-03-15 04:00:00 UTC, 2011-03-30 04:00:00 UTC ,2011-04-15 04:00:00 UTC ,2011-05-30 04:00:00 UTC ,2011-06-15 04:00:00 UTC, 2011-06-30 04:00:00 UTC ,2011-07-15 04:00:00 UTC ,2011-08-15 04:00:00 UTC, 2011-08-30 04:00:00 UTC ,2011-09-15 04:00:00 UTC, 2011-09-30 04:00:00 UTC ,2011-11-15 04:00:00 UTC, 2011-11-30 04:00:00 UTC ,2011-12-15 04:00:00 UTC, 2011-12-30 04:00:00 UTC ] As always I encourage feedback, criticism, suggestions and pull requests. -Chris