This is one of my teenage years' favourites. We spent hours on dark December evenings in our cabin up in the Norwegian fjell, playing Scotland Yard. The rules are easy to understand and it is a kind of hide-and-seek, with the group hunting Mr. X, who travels unseen and pops up every now and then. The only clues the group has are the tickets Mr. X uses to travel around London. It never gets boring, even after almost 30 years.
I managed to score a used box of the 1982 original Ravensburger "daylight" edition (pictured in the Listal listing) last year, which makes me happy :-), I just don't like the current "nighttime" edition.