Add more links to guides, specs, and demos

[CrazyPython]

Wanted: more links to guides, specs, and demos from people even lightly familiar with that technology.

Please comment the best spec, demo, or guide here, or send a pull request if you want to be credited in commits. If you do send a pull request, follow these guidelines:

Spec: Should be linked to from date
Demo or reference: Should be linked to from element name
Guide: Should be linked to from description