Every time I mention this on HN, at least 15 people upvote it - which means they didn't know about it. So I feel obliged to repeat it again and again (as I usually use this method a few times a week and it's tremendously useful for me):

If you want to get Google's cached version of a webpage, just type

    cache:[url]
    e.g.: cache:http://johnkary.net/git-add-p-the-most-powerful-git-feature-youre-not-using-yet/

in the search bar and press return.

EDIT: 14 already, after an hour!