If you are staying in Annecy, do not miss the Gorges du Fier which is only 10 km away.
A natural wonder, walk on a footbridge through a spectacular narrow canyon, admire the Mer de Rochers....
Before or after your visit, you can also have a BBQ there or a swim (but the water can be cold).
A few advices: not really suitable for kids under 4, take a jacket (as most of it is on the shade and there can be a little breeze, wear good walking shoes, closed during winter season, be careful if you have vertigo...
Above the Gorges, you will also find the Château de Montrottier, built between the 13th and 15th century (http://www.chateaudemontrottier.com/en/historique.html)
Its role was to supervise the road from Chambéry to Geneva.
The view from there and the garden are wonderful, inside this medieval castle, you will see some weapons, furnitures, the dining room...