There is not many skiresorts open in may so if its that kind of skiing the options are kind a limited. Check out Folgefonna, Stryn and Galdhøpiggen/Juvass and see when they open for the seaseon. If you're into backcountryskiing may is the perfect time to go skiing. Close to Drammen you have Gaustatoppen. About 2 hours. And you find runs for most skill levels there. If you have several weeks you should really consider the areas already mentioned here. Lyngen is awesome in may. From mid may you have the midnight sun so you can go skiing 24h a day if you like:-) I still remember trips there last winter, 1 o'clock in the night, the sun is up and you ride in powder!
