If you are renting a gite in Brittany near Dinan, I would advice you to visit the aqua park, Cobac Parc. Located in Lanhelin, on the St Malo - Rennes road. GPS coordonates: 48° 26' 12'' Nord/ 1° 50'2'' Ouest.
It is well sign-posted - if, like me, you don't have a GPS - you should find the park very easily.
Once you have paid to get in (€16 from the age of 12 onwards, €13.50 between 3 and 11 years old), you can spend the whole day there and have access to 30 different rides.
You can bring your own picnic. If you don't fancy carrying it all day you can leave it in the car. They will stamp your hand so you will be able to get in and out of the park without any problems. They have several picnic areas.
You will of course find food there (burgers, chips, sandwiches, pizzas, drinks, etc).
In June, July and August, the pool area is open from 1pm. Beware, boys are not allowed to wear shorts! They have to wear swimming trucks!
It is a great day out for children (and adults!).
Cobac Parc has new attractions each year, so if you have been there before, you might discover new attractions this year!
For more information, you can visit their web site here.