Microsoft has documentation about turning an e-mail message into a meeting request, at least for Outlook 2003:
Turn a message into a meeting request - Outlook - Office.com
http://office.microsoft.com/en-us/outlook-help/turn-a-message-into-a-meeting-request-HP003064164.aspx
But now I would like to do something that is, in a sense, the opposite: I want to forward a meeting request to another person, but as a simple/plain email message (NOT as a meeting request), in Microsoft Outlook 2010. How can I do that?