Chris Slade describes the son et lumiere presentation at the abbey of Bon Repos called "Le Pays de Conomor" in Brittany, which takes place during the first two weeks of August.
If you are looking for a bus around Rennes or from Dinard to Rennes, try this link here. It is even in English.
I use the bus to get to Rennes station when I travel by train.
The bus actually takes you to the station (about 50 m from the front door!).
It is only 2.50 euros per person for the trip (1 hour long). Not bad!
Does anyone have a link to a good bus timetable website for Brittany? If so, please post it here.