Flumet has a lovely swiming lake ("plan d'eau") that's about 500m long.  From the chalet, it's a ten minute walk along the quiet road up the hill, then a footpath that winds down through woods to the far end of the lake (alternatively walk through the village, or park at the end of the lake)  At breakfast time, you'll have the lake to yourself (as in the photo below).  On a sunny afternoon, it's full of families with children and supervised by two lifeguards. There are two cafes -- the one near the village is good for a cheap plate of chips, and the one at the other end is more suitable when you want to have a nice salade nicoise for lunch.  If you go out in the car for a walk, remember to pack your swimsuits so you finish the day with a dip to cool off.