Don't know much about Greensboro, but I know Raleigh, Durham, and Charlotte are both under 2 hours away. Plenty of museums, night life, fancy restaurants, shopping etc if you find Greensboro lacking. Raleigh in particular has a lot of museums and historical sites.
Old Salem in Winston salem (30 minutes away??) is a popular tourist attraction though I haven't been there yet.
+1 on zoo - pretty neat and you can spend a day there. Fairly affordable, ~$8-10 IIRC.