This is one of my favorite places in the whole world. It is an enormous waterpark located in New Braunfels, Texas. The name "Schlitterbahn" (which means "Slippery Road" in German) accurately reflects not only the character of the park but also the deep-rooted German heritage present in New Braunfels.
This park is actually made up of six different water parks. The traditional section of the park is my favorite. Its motif centers around an ancient German castle. Some of the tube slides start at the castle, and one even goes through the castle. The other defining aspect of the old section of Schlitterbahn is that the rides use untreated water taken directly from the Comal River. This may seem gross to some noders out there, but I find it to be quite festive. There are nets to filter any unwanted "guests" out of the rides, but it is satisfying to look into the river flowing next to the ride and seeing a turtle just sitting there.
The newer sections of the park use chlorinated water for their rides. One of the sections (named "Blastenhoff") features "water roller-coasters" which all stem from a concrete platform about 200 feet in the air. After climbing into a two-man inner tube you are launched away into oblivion down a steep drop, only to be propelled back upwards by a stream of water. This concept has won Schlitterbahn lots of recognition, and had attracted many more fans.