The first US penny was minted the same year that the US Constitution was ratified, 1787. It was minted by a private mint under contract by the newly formed United States Government. The motto is something that stands out for me.
According to Snapple "Real Fact" #163, the motto printed on it was "Mind your own business." This is not exactly true - though close. The actual motto printed on the 1787-1789 "Fugio" penny was "Mind your business." The face of the coin contained 13 linked rings, the phrase "We are one," and the words "United States". The reverse contained a graphic depicting the sun shining down on a sundial, with the word "Fugio" printed next to it. Fugio is Latin for "I fly." Combined, the image and the word mean "Time flies." The motto of "Mind your business" is still up for debate, though it has been suggested that it could mean 'business' literally, as the coin was reportedly designed by Benjamin Franklin, who was a rather successful businessman in his own right. It has also been suggested that it may have meant, "time is short, do your work." I'm sure any number of other historians may have any number of other possible meanings for the motto.
Anyway, I just found that to be a rather interesting, little known piece of U.S. history. Here are a few photos of the coin:
A line drawing showing the original detail of the coin.
The face of the coin.
The back of the coin.
The Fugio Coin, from coins.nd.edu
The Fugio Cent, from Wikipedia
1787 Fugio Coins, from CoinFacts.com