Thanks for the tip. I always forget about these because the domains they use are usually too silly (they should just let us use raw IP addresses); and also because I use email so infrequently. Mailinator seems the only one I remember. There's another disposable email provider... I can't remember the name... the accounts are time-limited. Truthfully, it's an email forwarder; they ask for a personal email address. (Maybe you could forward to another disposable email provider.) You can choose to have the account last hours or days. I know I've seen it mentioned on HN.
Like Mailinator, this is a great idea.
Kudos to these guys for putting their mail admin skills to good use.