[Your letterhead, if desired; if not, your return address]
[Date of letter—month, day, and year]
[Recipient's first and last names]
[Street or P.O. box address]
[City, State ZIP code]
Dear [recipient's name]:
I am writing to apologize profusely for the way I behaved at your organization's summer carnival on June 16th. I really let my strong feelings and opinions get the best of me and should have expressed myself in a much calmer, more diplomatic and respectful manner. Please call me when it is convenient for you to do so, because I would like to discuss this a bit more and make sure we are on good terms again.
Thank you for your time, and again, I apologize for my inappropriate and unacceptable behavior. I look forward to talking with you soon.
[Sender's first and last names]