Milton Bradley, 1990, 2-5 players, ages 10-adult. This is a tremendously entertaining game, although strictly for gaming nerds such as myself (IE, don't break this out at your family's Christmas party). I don't do role-playing games anymore (I just can't take them seriously), but HeroQuest allows me and my friends to revisit the dungeon crawling days of our youth by providing nice, simple, pre-fab dungeon scenarios and characters to play in them. I love being the ref and my buddies have a blast blowing through the pre-designed adventures. The game comes with dozens of miniatures (figures, doors, furniture, et al) and a book describing how they are to be situated on each level. Each level has some sort of mission the 4 heroes must accomplish in order to advance to the next level. A typical evening of gaming at my house ends with a round of HeroQuest (one level's worth) and a lot of drinking and yukking it up. It takes about 30-60 minutes to complete a level. The base game has 14 levels and there are various add-ons that provide new adventures (Return of the Witchlord, Keller's Keep, The Wizards of Morcar, Against the Ogre Horde, Barbarian Quest Pack and Elf Quest Pack). There is also a British edition produced jointly by MB and Games Workshop called the "Advanced Quest" edition. It includes everything that comes in the normal HeroQuest box, plus a 13 level "advanced" quest and 16 additional "citadel" miniatures. The citadel minatures are interesting inasmuch as they are configurable with multiple different weapons, giving the ref more options for toasting the players. The game is simple for first-timers to learn and get going without having to engage in a lot of rule-book reading. All in all a "must have" for those who don't have the time or patience for full-blown role-playing and just want to get right to the hack'n'slash dungeon crawling.
There is also a game from Games Workshop called Advanced HeroQuest about which I know not much. It's not played with plastic figures, so it doesn't interest me (playing with the toys being 99% of the fun here). AHQ has an add-on called "Terror in the Dark" about which I know nothing at all.