That car show thing is going on in Geneva.

I know you said they aren't much into museums, but the Red Cross Museum is a MUST see I believe. Some things there are quite powerful there.

IF the rain lets up. Signal de Bougy is fun and free. Lots of kids things, but as an adult, I have fun usually. Rip cords and such. And the Aubonne Arboretum is close for some nice nature walking.