A great one for people with kids

This is so simple but has endless posibilities. It's kind of an electronic time capsule, where you can type an e-mail to send to yourself at a later date.
Other companies offer this service but there's always the danger that they'll cease to exist when it's due to be sent. However given that this one is from Forbes, at least it's got some good backing.
There's also obviously the problem of maintaining your e-mail address so it's probably better to use a webmail address rather than an isp address which you will more than likely change.

It would be great for someone with young kids who could type an e-mail to send to themselves in 10 or 20 years time :o)

Link