You gotta love it when a community of developers congregates around some exciting hardware. That's certainly what's happened with the Pebble smartwatch: it's been getting steadily more capable ever since its release, thanks in no small part to Android and watch app developers. We've seen apps link the Pebble and the popular automaton engine Tasker before, but PebbleTasker (catchy!) does it better than anything else so far.
This go-between app will install a companion app on the Pebble and allow you to assign any three tasks you want to the top, select, and bottom buttons on the right edge of the watch.