Just a quick note here: We were travelling through Ogden, Utah and happened to stop at the Solomon Center - home of a world of fun, including one of these "FlowRider" surfing contraptions. The basic principal involves some sort of molded wave shape that is about 5-feet tall combined with a MASSIVE water pump that pumps a constant stream of water up and over the wave shape (you can Google "FlowRider" to see some pictures and videos to make the whole idea make sense). So, you can surf on this artificial wave because the constant stream of water pushes you up the hill while gravity pulls you back down. It is a blast!!!
I remember seeing one of these in San Diego, and I've seen commercials with them on cruise ships. They must be other places too. I highly recommend giving it a try if you get the chance.