Dungeons & Dragons
Dungeons & Dragons (often shortened to D&D) is a tabletop role-playing game that has had a tremendous history. It is the first fantasy roleplaying game created for the mass market, created by Gary Gygax in 1974 as a fantasy adaption of military strategy board games. There have been several editions of the game so far; its latest edition, 4th Edition (normally shortened to 4e) is under the helm of Wizards of the Coast, and enjoys popularity among newcomers to the RPG genre and those that have acclimated to the field on MMORPG games.
As the original 4e has swollen itself to a beast beyond its original design, Wizards of the Coast has released an Essentials line of rule books to get newbies much more acclimated to the basic parts of the game. The classes are different, the system is more akin to previous editions, but it all still holds itself under the 4th edition banner.
The game consists of several dice, ranging from 4-sided (D4) up to 20-sided; a game board or an online simulator (such as OpenRPG and MapTools); miniatures to represent monsters or players; and character sheets representing each character and his/her stats. Players take the role of a character, which can be created from a large variety of races and classes or roles, spanning the usual stereotypical roster plus some unique choices and combinations. These characters often come with simple or lavish backstories made by the player explaining their presence in the world that they participate in, and how they came to be who they are.
Each game is spearheaded by a Dungeon Master, who is a sort of referee and also the story creator of each campaign; he does not participate in the story as a character, however. It is the job of each player to, as a team, solve puzzles, roleplay as their character, and fight in encounters, all of which is set up for them by the DM.
Combat between the characters and the monster encounters are determined on a grid and solved by a series of dice rolls, depending on the situation. A D20 (twenty-sided die) is the main die of the game; it is the basis of all skill checks both in and out of combat, as well as attack checks. Four-sided, six-sided, eight-sided, ten-sided (single digit), and twelve-sided are also common dice to use.