Text Fiction - Play classic text adventure games like Zork or the Hitchhiker's Guide to the Galaxy on your Android smartphone for free!
textadventures.co.uk - Create, play and share text adventure games.
Mudlet - Mudlet is a freshly-minted MUD client, designed to take mudding to a new level.
Twine - Twine is an open-source tool for telling interactive, nonlinear stories.
Windows Frotz - Windows Frotz is an interpreter that can play all the old Infocom text adventures.
Ink by Inkle - ink is a popular open source scripting language for branching stories, designed for writers