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 username@mailinator.com 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 “bob@mailinator.com“, 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.