This one is a bit early for an April Fools joke depending on what parts of the world you are in right now. In any case, you have to hand it to them for creativity =). Link at: http://mail.google.com/mail/help/paper/more.html. Although, wouldn't it be scary the day Google enters into the paper advertising business as well?
I especially enjoy their picture below.
The one above was good...but I have to say they went a little overboard with this one though: Google TiSP.