Rocks 'n' Diamonds is basically a Boulder Dash clone. It was developed by Holger Schemel of Artsoft Entertainment.
RnD was one of the greatest Linux games I played back in 1996 when I got Linux. This game ruled. It had great graphics, and comparatively speaking it still looks pretty good. Great sound effects and music too! The idea of the game is simple enough: Collect certain amount of diamonds from a mine (without making the whole mine collapse, or nasties living there to get you), and head to the exit.
New releases got even better! The original game came with a level editor, but the new versions came with whole new game variations and level packs, including clones of original Boulder Dash, Supaplex, Emerald Mine, variation of Sokoban, and such. The new versions also include network support for 4-player game. It is a very entertaining simple game that has stood the test of time.
Originally a shareware game, it's now distributed under GPL. It runs under various UNIX clones (and SDL is supported), and also under Windows and MS-DOS. It has also been known to run under BeOS and Mac OS X.
Home page: http://www.artsoft.org/rocksndiamonds/