What is art?

I like to think I appreciate fine art, paintings, sculpture, etc, but lacking an education in art, I sometimes do not know what is good versus bad art. I just discovered The Museum of Depressionist Art, which helps me quite a bit. My favorites from their collection are Fog, Last Supper on Toast, and The Shroud of Hoken. The description of Pork Brains With Gravy is priceless. The Big Bruise explains how one man discovered he was an artist.