Chute

manifest.json

{
  "update_url": "http://clients2.google.com/service/update2/crx",
  "name": "Chute",
  "description": "Occasionally interrupts your work with a parachute jump.",
  "version": "1.0",
  "manifest_version": 2,
  "content_scripts": [
    {
      "matches": [
        "http://*/*"
      ],
      "css": [
        "chute.css"
      ],
      "js": [
        "chute.js"
      ]
    }
  ]
}