"You wake up," the computer screen says. "The room is spinning very gently around your head. Or at least it would be if you could see it, which you can't. It is pitch black."

At this point a prompt appears on the screen, indicating that it's my turn to say something. I type in, "Turn on the light."

"Good start to the day," the computer responds. "Pity it's going to be the worst one of your life. . . . "

With that cheerful assurance from my friendly local microprocessor, I'm off and running on another session of a habit-forming little computer game called "The Hitchhiker's Guide to the Galaxy."

If that title brings to your mind the delightful series of pseudo-sci-fi novels by Douglas Adams (the series that begins with "The Hitchhiker's Guide . . . " and ends three volumes later with "So Long And Thanks For All The Fish"), then it's a safe bet you'll love the computer game derived from the books. But even if you've never heard of the Adams books, you're likely to find this game diverting.

At this point the reader who uses a computer for nothing more exciting than totaling last month's receivables may be wondering why he or she should get interested in the Hitchhiker's Guide game, or any computer game, for that matter. I know three good reasons: For one thing, computer games are fun; for another, they're fun; and finally, they're fun. If that's not good enough for you, you may go back to your spreadsheet and forget I ever brought this up.

"The Hitchkhiker's Guide . . . " program is an example of a genre of games called "interactive fiction." The games are fiction because they involve elaborate plots peopled by complex characters in exotic settings; they are called "interactive" because the central actor in each game is the player -- that is, you. You decide what to do or say next, and the computer responds.

The acknowledged master of computer- ized interactive fiction is the software house Infocom. It makes more than a dozen inter- active games, from the "Zork" series -- three discs based on the Dungeons-and-Dragons "adventure" game -- to a set of complicated murder mysteries that the player is expected to solve.

Like almost all software, the Infocom games are overpriced: around $40 at retail, although some mail-order houses offer them for $25. They vary in content and complexity (degree of difficulty ranges from "Introductory" to "Expert"). But they have certain characteristics in common. They employ strictly text, no graphics; the computer talks to you, and you talk back. They are adept at understanding plain English: You type in "Ask Mrs. Robner about the new will," and a grieving widow fills you in on the changes her husband made in his will just before his murder.

Each Infocom program requires you to solve a series of verbal puzzles that are necessary to achieve the ultimate goal of the game, whether it's apprehending the murderer, safely traversing the enchanted forest, or whatever. If you get hooked on a game but can't solve it, Infocom supplies (for $8 each) books of hints to help you out.

Typical of the puzzles is the first dilemma you face when you wake up in the pitch-black room at the start of "Hitchhiker's Guide." You can get out of bed and walk to the door (you do this by typing in directions such as "get out of bed" and "go to the door"). But since you're suffering from a bad hangover, you can't get the door open. You have to figure out which of the various tools around your bedroom to use to get out the door. The solution -- not entirely logical, but then this whole game is charmingly illogical -- is to take an aspirin that will soothe the hangover and let you get a firm grip on the doorknob.

I find these games -- particularly "Hitchhiker's Guide," which is the funniest -- enjoyable now and then. I haven't tried all the Infocom offerings, so I sought an assessment from a guest expert, Homer Reid, a 10-year-old computer game wizard.

My expert ranked Infocom's "Wishbringer," a fantasy tale involving mysterious letters, magic stones, etc., as the best of interactive fiction games: "It's fun and it's pretty easy, so you don't get frustrated." He gave a mild thumb's up to the murder mystery game "Deadline" -- "Once you get the basic idea, it's fairly interesting" -- but panned another mystery program called "Suspect." "It stinks," my expert concluded.

If you can't find these games at a store or from a mail-order outfit, Infocom (125 Cambridge Park Dr., Cambridge, Mass. 02140) will put you on track.