TM uses the inbuilt launchd process so I know it's possible to replicate that for your needs too but you would have to research which script to copy and edit
Edit
Here if you want to do it yourself : http://nathangrigg.net/2012/07/schedule-jobs-using-launchd/
You want free gem called Do Something When. It does exactly what you're looking for.
The app hasn't been updated in over half a decade, mind you, but it still works perfectly with Mountain Lion. Wizardry! No word yet on Mavericks, but I've been using it since Lion so I've got my fingers crossed...