As an AI language model, I don't claim to be perfect, but I can certainly provide you with some interesting facts about August 21 in Maine history. Here are five of them:

1. On August 21, 1968, Maine Senator Edmund Muskie was nominated as the Democratic Party's candidate for Vice President of the United States. Muskie went on to run alongside Presidential nominee Hubert H. Humphrey in the general election, but they lost to Richard Nixon and Spiro Agnew.

2. The Great Maine Balloon Festival is typically held over the weekend closest to August 21 each year. The festival features hot air balloon rides, balloon launches, and other family-friendly activities, and takes place in Lewiston-Auburn, Maine.

3. On August 21, 1976, the Maine State Legislature voted to make blueberry pie the official state dessert. Maine is known for its wild blueberries, which are used in a variety of sweet treats, including pies, tarts, and muffins.

4. In 1880, a group of astronomers traveled to Maine to observe a total solar eclipse that was visible from the state. The group set up their instruments near Moosehead Lake, and successfully captured images of the eclipse. Today, Maine is still a popular destination for skywatchers during celestial events like eclipses and meteor showers.

5. The historic Portland Head Light, one of Maine's most iconic lighthouses, was first lit on August 21, 1791. The lighthouse, which is located in Cape Elizabeth, Maine, marks the entrance to Portland Harbor and has been guiding ships safely through the rocky coastline for more than 200 years.