Boat trips....
A visit to Brittany would be incomplete without a boat trip.
There are a dozen or more accessible islands off the Brittany coast, and most of these can be reached for a day-trip from the nearest ports. 
In Finistere, there are boats to Ouessant and the Ile de Sein from Brest or Audierne.  Or trips to the tiny IlesGlénan are available at Concarneau.  
In Morbihan, there are ferries from Quiberon to Belle Ile en Mer, the largest of the Breton islands, and ferries to the little Ile de Groix from Lorient.Celtic Brittany....
Brittany is famous for its ancient monuments, the most famous of which are the standing stones of Carnac. 
A few towns to visit....
Concarneau (Finistère)
One of the great traditional Breton fishing ports - all the atmosphere of a traditional Breton port.
Dinan (near Saint Malo)
One of the most visited historic towns in Brittany, with ramparts, old streets and old houses, plus plenty of tourist boutiques.
Josselin  
Attractive old town, with a magnificent chateau, with gardens and a doll museum.
Quiberon (Morbihan)
At the end of a long and very narrow isthmus, Quiberon stands as on an island in the gulf of Morbihan. It is an attractive small town, with port, plenty of beaches, and boat trips to the islands.
Nantes-Brest canal
Though it no longer links the two cities, the canal, running westwards from Redon, is an attractive trail for boating, hiking or cycling. The canal (and rivers that form part of the waterway) is navigable from Pontivy to Nantes, via Josselin and Redon.
Saint Malo
Fine walled and fortified granite city at the mouth of the river Rance - the most visited city in Brittany - once the home of explorers and pirates, now more popular with yachtsmen.

Locronon (Finistere)
A very well kept quaint village. Superb stone buildings, picturesque.
Quimper
Not only is Quimper the administrative capital of the Finistère department, it is also generally regarded as the cultural heart of Brittany. The town is known for its cathedral, atmospheric old quarter and museums but most of all for its annual festival celebrating Breton culture.
Vannes
The walled town of Vannes is without doubt one of Brittany’s most attractive sights and a must-visit on any trip to Morbihan. Wander around the well-preserved medieval streets before enjoying a harbour-side lunch then taking a boat trip around the gulf. Kids will love the aquarium and butterflies.

http://www.france-voyage.com/events/festival-blue-nets-22.htm
One of the biggest traditional festivals in Brittany.

http://www.laroutedurock.com/
Independant music festival in Saint Malo

Not forgetting our local Fete de L'andouille in Guemene sur Scorff.....