This looks like a fun activity: hack email headers to mess with Outlook user’s heads!
Microsoft Outlook uses a rectangular bar above the message header to display information and warnings about the message you’re reading. It may report that you replied on such a date, that an attachment was suppressed, or that line breaks have been removed. Sometimes, though, you might see a very different message—perhaps something like “This message violates the USA PATRIOT Act” or “ERROR: Microsoft Outlook detected. Get a REAL email client!” As it turns out, anybody who can control the custom headers for outgoing e-mail messages can cause such a warning to appear. E-mail server administrators have this level of control, as do spammers, hackers…and you! Here’s how.
I’m not an Outlook fan, and I strongly recommend that other’s use a less-dangerous email client. But this sounds like a lot of fun! 
