Desktop Tower Defense is a Flash-based tower defense browser game created by Paul Preece in March 2007. The game had been played over 15.7 million times as of July 2007, and was one of Webware 100's top ten entertainment web applications of 2007. Desktop Tower Defense is available in an English, Spanish, German, French, or Italian interface. In May 2009, a commercial Nintendo DS version became available.
Source: Wikipedia, "Desktop Tower Defense", available under the CC-BY-SA License.