A roleplaying game, or RPG, is a game where a number of participants typically assume the roles of fictional characters.
Traditionally, an RPG was played by a group of friends with one of the group assuming the role of "game master" and effectively running the game. These are often called "tabletop" RPGs because they employ rulebooks, pen/pencil, paper and dice of assorted shapes. Nowadays there are a great number of RPGs available in videogame format - everything from online games designed for any number of players (for example World of Warcraft, Phantasy Star Online, and Everquest) to single player story led games (for example, the Final Fantasy series). Proponents of tabletop RPGs criticize computer and console-based RPGs for their relative inflexibility, since even the best computer-model can't be as ingenious as an actual game-master can.
Since the 1980s, RPGs have come under a great deal of criticism from groups who feel that playing these games is inherently dangerous, especially to children, and could potentially lead to insanity, murder, suicide, and occultism.
Others have argued that RPGs can be used to teach mathematics, problem solving, social skills, and critical thinking to kids, especially those who might have trouble learning these skills in a traditional environment 
- Dungeons and Dragons
- Vampire: the Masquerade
- Top Secret
- Empire of the Petal Throne
- Boot Hill
- In Nomine
- Bunnies and Burrows
Bad Tabletop RPGs
Please note that the tabletop roleplaying games listed below may cause feelings of disgust or shame if for some reason you attempt to look them up online. Essentially all of these are poorly-designed and many of them feature subtly (or not-so-subtly) racist, sexist, or otherwise bigoted ideologies inherent in their ruleset or backstories.
The "Unholy Trinity" of tabletop RPGs
- HYBRID - A confusing mass of unnecessarily-complex rules with no structured backstory, HYBRID was an attempt to write rules for reality using comic books. An utter failure, both unplayable and offensive. Given the nature of the Internet, HYBRID will likely be replaced by another yet-worse RPG in time.
Other notably-bad tabletop RPGs
- Spawn of Fashan - one of the first "bad" RPGs, generally thought to be a deliberate parody. The game is well-optimized for people who roleplay to ruin other people's fun.
- The World of Synnibarr - Considered a terrible RPG by many online and a "B-list" RPG worth playing for the hilarity by others, the badness comes not from poor design (like virtually every other title contained herein), but from the ridiculous-by-any-standard setting. An infamous example of a typical Synnibarr monster is a flying bear with laser-beam eyes.
- SenZar - Perhaps better-designed than most of the games on this list, the balance between classes is still terribly off (even more so than the first edition of D&D). It also not only allows but openly encourages abandoning roleplaying in favor of optimizing one's character, a tack that offends many roleplayers.
- deadEarth - Ridiculed for claiming "realism" while simultaneously having comic-book-level powers gained from radiation exposure, including a table of 1000 random powers included in the core mechanics. Given backhanded praise by some critics for a rule that is often interpreted as only allowing a single player to create three characters (ever, and characters dying during the creation process is not uncommon.)
- Phoenix Command - Not so much "poorly" designed as overdesigned, Phoenix Command and other games from the now-defunct publisher Leading Edge Games were the products of a rocket scientist attempting tabletop RPG design.
- Wraeththu: From Enchantment to Fulfilment [sic] - Almost as oversexualized as the Unholy Trinity above, Wraeththu is one of the most recent additions to the ranks of legendarily-bad RPGs, and boasts what is almost certainly the only extant depiction of an alien penis on the cover of a tabletop RPG rulebook.
The role of the game master is four fold: author, director, referee, and (commonly omitted) manager.