your actual email address?
some email address you own but never use?
random typing?
For as long as I can remember, I've always entered "me@me.com" Not sure why, but I do. If you are "me@me.com", and you get a bunch of sysadmins angrily emailing you to quite downloading the same file over and over (I have a bad habit of d/ling software into virtual machines that I then blow away and need to fetch again), I apologize.