This really comes handy, as
email@example.com is usually blocked. Maybe they'll come up with some kind of random domains that change on a daily basis. Shouldn't be that expensive.
Usage: You don't need to sign up for this service. Just start using your address with some more or less random name in front of the "@". If you want to read your mail, go over to
mailinator.com and enter that address. As no password is required, you shouldn't use this for sensitive information and I suggest using a random name that at least hide your login information and such.
Tip: They provide RSS-Feeds for your inbox, so you don't have to check your spambox every five minutes....