If you are fed up of galettes and crepes (I don't think this is possible but let's suppose so), go to Chez Dede, the pizzeria serving the largest pizzas in Rennes. The "tire-fesses" is particularly worth trying with reblochon cheese. Plus you get a Carambar if you manage to finish your pizza!
34, Rue Sainte Mélaine, 35000 Rennes
+33 2 99 87 10 83
Google map: bit.ly/qKOL5q