Joel found out this interesting (it is an old post so you might already have read that) free mail service with a difference. It's called Mailinator. You don't need to sign up here. The service is meant to ditch the spammers, just pick up any and you can check your mail at this account simply by visiting their site and typing your username. The mails are deleted every few hours, you can store a maximum of 10 mails and no attachments are accepted. Here are few picks from their FAQ:

Um.. if there is no password, can't someone else get my email?
Yup. For this reason, you might want to pick an offhand name. Don't pick ““, maybe you'd be better off with “boohabunny”. In any case, its perfectly possible for anyone to see your email here.

This sounds pretty insecure. What if I send important emails with sensitive super-secret information in them to mailinator?
Then you are a stupid-head. That isn't what this is for.

What if I want my emails to stay in my box longer than a few hours?
First off.. it isn't “your” box. Its anyone's box. Just because you pick a name doesn't mean diddly – you and anyone else can use it at the same time. Secondly, if you want your email to stick around longer than a few hours then you need a normal web-email service, not mailinator. Check yahoo or hotmail or something.