Grasse is widely known for its perfume; there are 3 factories that are still open to the public, and make for a really interesting day out as you learn all about how perfume is made, and may even leave with a couple of freebies. The old town is absolutely beautiful, with lots of hidden streets and old buildings, a few churches and some wonderful squares.
The annual festival held in August is the Fete du Jasmin. The old town is draped in jasmine flowers for as far as you can see, there are floats made out of flowers that are paraded through the streets. In the evening you can admire the fireworks while listening to live music.
If you're interested in having a day out, you can join one of the walking tours around Grasse and learn all about the history of the town, or you can go and visit the caves and grottoes in the surrounding areas.