Mailinator - Any Inbox. Any Time.
Guerrilla Mail - Guerrilla Mail is a web-based app that provides a disposable and anonymous email address. Users of the service are not required to set up an account in order to send or receive emails.
10 Minute Mail - Temporary disposable e-mail service to beat spam. Avoid spam with a free secure e-mail address.
MailDrop - maildrop is a Mail delivery agent used by the Courier Mail Server. The maildrop MDA also includes filtering functionality. maildrop receives mail via stdin and delivers in both Maildir and mbox formats.
YOPmail - YOPmail is an interesting anonymous mail program that allows users to communicate with each other without compromising their original email addresses. Read more about YOPmail.
Bouncr - Bouncr allows you to hide your permanent email address behind an '@boun.cr' address.