Actually, we DID have coed sleepovers in my APO chapter.
We had our chapter planning retreat at a Boy Scout camp near IU and we all slept in the main cabin in our sleeping bags on rows and rows of bunk beds. Not a very erotic atmosphere.
We also had a sleepover at our chapter president's house following an exec meeting. There were less of us there but we all slept in the living room and dining room. Lots of fun.
Other things we did: service projects (duh!), movie nights, bowling, roller skating party, hayride, picnics, barbecues, dancing, dinner at local restaurants as a chapter, etc. etc. There were lots of things for us to do. And we weren't very artsy-craftsy either.