Almost short enough to text as a follow up to a conversation. When "less is more," this says just enough.
Sample Emailed Invitation
Subject: Wondering if you can come...
Just following up... I am pulling together a discussion with some guys. I am reaching out to you because I am really curious about what you think about this stuff. The discussion will be: Questions about God—Tuesday 2/21 at 7:30p - 9:00p. We will probably discuss this question: If you could ask God one question and you knew you would get an answer, what would you ask?
I would love to have you there. Let me know if you can make it.
Have a great day![name][address][cell phone][home phone]