Milton Bradley, 1985, 3-6 players, 10-adult. In Scotland Yard, one player plays "Mr. X" and the other players play investigators attempting to capture said Mr. X. The action takes place on a large map of London, with each player starting out at a randomly determined location on the board (of which there are at least a couple of hundred). The investigators place their markers on their starting squares, whereas Mr. X's marker remains off to the side (for the time being). Each square is connected by up to three different transit routes (Bus, Taxi or Subway) and each player starts out with a supply of transit tickets (color-coded for each of the three transit types). Turns consist of an investigator (or Mr. X) selecting an adjacent square to move to and paying the appropriate fare. Mr. X's movements are recorded in secret (a little plastic template sits on top of a piece of paper - Mr. X writes down his new location in the corresponding hole in the template and then covers it up with the transit ticket he used). For an investigator to win the game, he or she must land their investigator token on top of the space occupied by Mr. X. For Mr. X to win, he must strand all of the investigators (land them in squares where they have run out of the appropriate transit tickets with which to continue moving). Every five turns (or so), Mr. X "surfaces" and his token becomes visible on the board for one turn (after which he then slides back into the shadows). It is the goal of the investigators to move in on Mr. X and then guess his movements (based on his last known position and subsequent transit tickets played). Mr. X has the added advantage of being able to play two consecutive moves (up to three times per game), as well as playing "black tickets", which allow him to move on any transit line (without disclosing which it was). This game is quite fun, but I'd say it's mainly designed for a family setting (I can't see a group of adults pulling this one out). It's easy to learn and plays very quickly. I'd venture to say that it might even teach some important tactical lessons to the wee ones - as Mr. X, they must carefully plot (and keep track of) their moves, whereas as an investigator, they have to employ logic in order to figure out the best moves to home in on, and eventually trap, Mr. X.
This game was originally released in Europe by Ravensburger (circa 1983), where it won the German Game Press "Game of the Year" award.