Are you tired of the 15-251 Grades website (for Fall 2014) being broken? Yeah, me too. That's why I made this website and this Chrome extension.
This Chrome extension is NOT listed in the Chrome Web Store because I don't want to figure out how to pay Google 5 bucks. So you're going to have to install it manually, unfortunately. In Chrome, go to chrome://extensions/ and drag the .crx file from File Explorer/Finder/Nautilus or whatever into the web page to install.
Note that you cannot install extensions in this way on Chrome Stable on Windows. The best solution I can think of for that is to use Chrome Canary instead.
This extension should turn its icon green whenever the grades website is online and red when it's not. It should also give you a Chrome notification whenever the status of the website changes (within one minute of it happening, at least).
And no, I didn't make this for Firefox/Safari/IE because I only have so much time while taking 251, and also most people at CMU use Chrome (and the API was great).