LexJongg was, according to the author's Web site, written in nine hours. This may be a pretty impressive feat of coding, but its result is less remarkable. The free LexJongg is a fully functional, yet decidedly sub-par, MahJongg variant.
LexJongg has the "classic" computer MahJongg play: Match two tiles to remove them, repeat until all the tiles are removed or you can't move anymore. While this gameplay is still fun, LexJongg lacks any of the features one expects from even shovelware games these days: There is no sound or animation, there is only one tile set (of graphical symbols such as smiley faces, Batman masks, and Windows logos, hence the name), and only three layouts, one of which is randomly picked for you when you start the game. The game controls are limited to "start" and "exit", with no hints, rescrambling, or other features. The website is copyright 2003, indicating no updates likely in the near future.
Why play this particular MahJongg? LexJongg is one of the smallest-footprint MahJongg variants I've seen; if you want something to run on that teeny-tiny netbook you just bought, this might fit the bill. If you have any disk space to spare, though, you might want to look at a more robust variant, such as MahJong Towers Eternity, which boasts over 40,000 layouts, or MahJong Suite, with its many many tilesets.