MockMyID is a BrowserID Identity Provider (IdP) that will gladly issue assertions to anyone and everyone, without a second thought.
It's like Mailinator, for BrowserID.
It's especially useful for testing and demoing sites that depend on BrowserID, since you don't have to set up email or accounts beforehand.
How Do I Use It?
Whenever you're asked to log in with BrowserID, just make up any email address