Dungeons & Dragons
For those of you who are unaware but curious as to what this whole Dungeons & Dragons thing is all about... Really, it's quite simple.
"The core of D&D is storytelling. You and your friends tell a story together, guiding your heroes through quests for treasure, battles with deadly foes, daring rescues, courtly intrigue, and much more."
-Wizards of the Coast
In a bit more detail, You and your friends create characters, and using those characters, you play through an adventure, guided by a Dungeon Master, or DM. Each "adventure" you and your friends partake in advance the characters that you have created making them more powerful, and allowing them to take on even more dangerous adventures. These groups of adventures, or "Campaigns" all fit together to make one larger story.
These stories can be "pre-made" or you can make your own "homebrew" stories, either way. They are fun to play, and it's a great time spent with friends!