MockMockWeb is a Heroku-ready Node.js-based Web application server which allows you to mock up a website in seconds. It allows you to instantly launch a website which sends an empty page (with status 200) to any request/URL and edit any page on the spot. You can also edit the layout shared throughout your website. It lets you build a mock (sometimes real) website in a request-driven interaction.
MPDisco is a Node.js-based music server built to let teams and groups control a single music player together. Accessing an MPDisco server puts each user, after logging in, in a rotating DJ queue. Each user will be given one hour (by default) to control the playlist and music player.