If you're a fan of Dungeons and Dragons or other paper based RPG's you'll want to check out Chat & Slash, a Slack RPG that is currently going through its beta.

If you aren't familiar with Slack, it's a messenger system used by businesses to connect teams and employees  (similar to a profession Skype/MSN messenger). Friend of the site Dan Hulton used its API to create a paper and pen RPG - which you can sign up for right here. Slack has apps for PC and Mac, as well as on mobile phones.

Chat & Slash is an old-school hack & slash RPG played using the Slack client with a highly customized bot.  It's quite similar to MUDs of old, but controlled via buttons and slash-commands.

If interested, you can sign up right here, and check the dev log here. Make sure to also follow Dan on Twitter.