website eggs?

So what would happen if you hid an egg, some type of hidden content, on your new website? Incentive people for find the egg, deposit money into their account, whatever, but advertise the fact that you’ve hidden this valuable thing on your new website to make your members explore it more?

It seems to me to be a cross between the “Magic Whistle” in Super Mario 3 and some Google job advertisements like this one.