My favourite traditional board game is Backgammon and the best version I have found for CP/M is The Peelgrunt Game of Gammon IV, v2.0 released 1st April 1986 by David C. Oshel. It is available on the Walnut Creek CD.
Gammon IV is a little unusual as play is set on another world and you are given a choice of three characters to play against, each with their own style. Other than that the game is much the same as any other version of Backgammon. The game is introduced with the following:
You are a passenger in the "Orion" bound for STAR WELL, a slightly disreputable planetoid in the Flammarion Rift, where you have a scheduled layover of several hours. You enter the Casino there, desperately bored. Your attention is immediately drawn to an unusual trio. Your instinct for good company (they are playing Backgammon) leads you easily into a round of introductions: LOUISA PARINI -- A young woman who gives you the uncomfortable feeling that she is even younger than she looks. In fact, she is the offspring of a clan of noted interstellar jewel thieves and con artists, on her way to a famous girl's finishing school on Nashua. She has larceny in her soul, but she is on holiday. Do not underestimate her. (But you will, of course. You must.) ANTHONY VILLIERS -- A mysterious young fop with impeccable manners, and (you notice) an even more impeccable dueling saber at his side. There is something between Louisa and him. His conversation is light, witty and just slightly cynical, but you are not wrong to conclude that this is someone you can trust. TORVE THE TROG -- This blue-eyed, golden-furred entity is a member of the most dangerous and unpredictable race in the galaxy (aside from humans). You are amazed that this one is allowed to travel. (In fact, Torve's papers were forged by a member of Louisa's family and procured for him by Villiers). Torve is lost in some inner rapture, emitting soft "Thurb"-like noises. You suggest a friendly game of backgammon, at small stakes, and your companions agree instantly. Who will be your opponent? (L, V, or T)
The game is quite flexible in that you can choose which way round you want to play, which stones you want to use, whether you want to use your own dice and you can even arrange the stones manually. The gameplay with each of the three characters is fairly good for beginners and I like how each of their personalities is expressed in their gameplay. The controls for the game work well and overall it is an enjoyable game to play.
Gammon IV is compatible with the 8080 and is configured for ADM-3A terminals by default. If you have a Kaypro or compatible system such as the Commodore 128 then you can press 'G' to enable a graphics mode which displays the stones using extended character graphics. You can configure the terminal by patching the relevant bytes in the .COM file or by altering the included C source code and recompiling with the Software Toolworks' C/80 v3.1 compiler.
Video of Gammon IV Being Played
You can see Gammon IV being played on a Commodore 128 in the video below: