HeroQuest - Interactive adventure in which players are both the hero and the storyteller. Players have the option to write additional chapters to the story. - http://www.digifort.com/heroquest/
Infinite Story - Extensible "choose your own adventure" stories. - http://www.infinite-story.com/
Iamcal Network - Add the next segment to the story in this rambling online adventure game about what happens after someone knocks at the door. - http://www.iamcal.com/games/choose/
Rendezvous - Interactive fiction with a speculative twist, romance and adventure in a Canadian mountain wilderness. View novel online or download the hypertext book. Requires fee to access entire story. - http://www.hyperlife.net/fiction/start.htm
Girlfriend Quest - Play a single guy on the prowl for a new lady. Find her in this choose-your-own-adventure type game. - http://www.swytpinay.com/gfquest/
The Neverending Tale - An interactive story-writing adventure for kids. Stories include: "The Magical Scroll," "Space Station Delta," and "The Haunted Castle." - http://www.coder.com/creations/tale/
A Story as You Like It - A hypertext story by Raymond Queneau. - http://www.thing.org/projekte/7%3A9%23/queneau_1.html
StorySprawl - Devoted to the creation of hyperfiction. Add your own chapter to one of many stories at this library. - http://www.storysprawl.com
SuperStory - Add a new episode to "Trevor and the Haunted Tomato." - http://www.hungrysoftware.com/online/story/
Suspicion of Murder - Solve a crime online in this mystery adventure game. It's free, it's online, it doesn't need a download. - http://www.suspicion-of-murder.com/
Tales from the Vault - An interactive story, where one can write parts of it or submit new stories to the vault. - http://www.talesfromthevault.com/
Gav and Peloso's Interactive Story - A choose-your-own-adventure type story, where a user gets to write the story when it runs dry. - http://www.nuc.berkeley.edu/~gav/wayfarence/welcome.html
Extend-A-Story - An extendable choose your own adventure story. Similar to The Addventurers. The story is created by the players. - http://www.sir-toby.com/extend-a-story/
The Addventurers - Interactive, extendable, choose your own adventure stories. - http://www.addventure.com