Not to be like a local Chamber of Commerce or anything but consider Corning, NY. 2.5-3 hours from Buffalo and lots to do for a 1 day visit.
(Edit: Just noticed Fairport below your avatar...even closer)
May 19-20 is one week before GlassFest which is pretty fun.
http://www.gafferdistrict.com/glassfest
But other weekends you can visit the Corning Museum of Glass which is pretty great as well as the Rockwell Art Musuem which is a small but nice one. Make your own glass is super popular with women in my experience (and admittedly, is pretty fun):
http://www.cmog.org/visit/make-your-own-glass
Market Street is fun to visit, lots of shops, bars, restaurants, etc.
Just an idea. If interested I am local and could help with some stuff.