DutchPIPE allows Web developers to make virtual multi-user "avatar" environments. Each Web page becomes an abstracted environment or location where visitors and other items on the page are visualized. This status is retained as visitors move around. A lot of real-time interaction is possible, resulting in persistent interactive page environments. DutchPIPE uses AJAX and the DOM for the browser, and it works without Java, Flash, plugins, or firewall adjustments.
ErisMUD is a MUD/MOO server/engine written in Python and supports many features: rooms, NPCs, items, player skills and stats, ANSI colors, a help system, damage/healing, etc. SQLite is used to store the data, so no files are required for building (unlike LPMUDs). Short and easy internal commands take care of the development and maintenance.