Edited wallzy's post for direct link!
Except that the forum software wants to put http:// in front of the URL you put in there and then scrub the colon (haha, scrub the colon) from the steam:// part. Stupid computers trying to be helpful

Just copy/paste the text to your address bar and and it works, but not that it matters now, because the sale is over! $19.99 for you!