http://www.artsology.com/index.html Fun, games, and art videos
http://www.johnmyatt.com/index.htm The biggest art fraud of the 20th century. John Myatt spent a year in prison. Fantastic skills.
http://www.cs.berkeley.edu/~sequin/SCULPTS/sculpts.html Fantastic sculptures, art and artists that are influenced by Maths.
http://www.greatbuildings.com/architects.html Website with an A-Z of architects and their buildings
http://www.diduknow.info/ Gallery site with guided tour
http://www.nga.gov/kids/ Great site were you can make changes to famous paintings (National Gallery of Art)
http://planetperplex.com/en/index.html Optical illusions and fun
http://www.renaissanceconnection.org/index2.cfm Great funny website on the Renaissance
http://www.zefrank.com/scribbler/ Make a line drawing and then set the scribbler away, its fantastic.