If any classic sci-fi books lend themselves to the CD-ROM game treatment, it’s Arthur C. Clarke and Gentry Lee’s Rama series. Based on Rama II, Rama lets you join a group of astronauts exploring a 50-kilometer-long cylindrical artifact from an alien civilization. In an admirably restrained, three-disc adaptation, players wander purposefully around the gigantic spaceship, get hints from fellow explorers (delivered in crisp, well-acted video clips), and encounter such extraterrestrial oddities as giant mechanical centipedes. And if you happen to get killed, the septuagenarian Clarke (who helped create the game) appears to offer encouragement and send you back to unravel more otherworldly mysteries. A-