The day to do all types of pranks to your loved ones!! :D
Here is some ideas:
http://familyfun.go.com/arts-and-crafts/season/minisite/april-fools-pranks-main-ms/
Oh and did you check out the Gmail on paper page??
http://mail.google.com/mail/help/paper/more.html
Very good and interesting idea but it's just a joke! :(