In CVS there is a new API for scheduling things - see updated version of time.html at http://twistedmatrix.com/users/jh.twistd/viewcvs/cgi/viewcvs.cgi/~checkout~/doc/howto/time.html?rev=1.5&content-type=text/html&cvsroot=Twisted As you can see, it's a much better API.