Cleveland Museum of Art would definitely rank in there somewhere. We moved to Cleveland in the summer of 2008 in order for my husband to attend grad school at Case Western Reserve University. His building was half a block from the Museum of Art. Beginning that year, we began the habit of visiting the museum at least twice a month. It is one of the places from Cleveland that I miss the most. Some of our favorite collections to view, and re-view, have been the Ancient Egyptian, Greek, and Roman Art as well as the Medieval Collection which contains an impressive weapons and armor room.
Last week we made a quick visit to Cleveland and journeyed to the museum for several hours one afternoon. On exhibit was a Contemporary Art Installation entitled Half the Air in a Given Space. Basically it was room full of balloons that you could walk through. You can see better pictures of the room on the museum's site (here), or on their Facebook page (here), but here are a couple of shots displaying my children and their friends that we visited with that day. If you're in the Cleveland area, the exhibit is on display until Thanksgiving.