Tommy's Towers is a program that plays a game that might be currently the largest chess variant one can buy on this planet at the moment.
`Tommy' is a company, selling lots of game programs, each for 6 US dollars. The company is located in Denver, and according to the publicity, is run by aliens from outerspace. All programs of `Tommy' are DOS-programs, with entirely character based screens.
One of the programs of Tommy is Tommy's Towers. This program allows two humans to play a chess variant against each other. The variant is played on a board of twenty by fifty squares; each player starts with an army with more than 300 pieces of 17 different types. Note that the program only allows people to play against each other; there is no AI that lets a computer play against you.
Additionally, the board has some terrain features: hills, pits, and bridges, that affect movement.
The variant thanks its name to the towers: these are the only pieces that can cross the entire board in one move. (The tower moves as a rook. Note that in several languages, the name for `rook' is actually a translation of tower, like `Turm' in German, and `Toren' in Dutch.)
More information on how to buy this game can be found on the website of Tommy's Toys.