Beside BrowserQuest, all the demos should work out-of-the-box. Just checkout this repo at the root of an HTTP server. You should be able to access the demos via file:/// (on a sdcard) too.
About BrowserQuest, the client (HTML code) is part of this repo. For the server (websocket), you need to checkout this repo: https://github.com/mozilla/browserquest (branch "mwc"), and follow the instruction in the README.
Add the IP of the websocket server in browserquest/client/config/config_local.json (this repo).