DXtris

DXtris is a Tetris clone written in C++ for Win32 platforms (Microsoft Windows 95, 98, and NT4).
It plays exactly as you'd expect a Tetris clone to play - blocks fall from the top of a well and it's your job to destroy them lest they reach the top of said well. However, DXtris is unlike most Tetris games available today. The graphics are impressive and the backgrounds lush, enhancing the overall feel of the game. There are also some unique special effects, such as the blocks actually falling and crumbling when you get a line. Plus, you have the option to play various game "types" such as a quick game of 25 lines or a race against the two-minute clock.
Sound effects range from a "thud" when a block falls into place to an applauding crowd congratulating you on a new high score. But the most interesting feature DXtris has to offer is in its customizability. Don't like a particular backdrop? No problem, just delete the associated file. Want to add your own? Create one in your image editor and import it. Also editable are block "skins" which change the appearance of the falling blocks in the well, down to the debris left over from a broken line.