I purchased an interesting state quarter error coin on ebay recently that was advertised as the "Rust Quarter." Some machine grease had gotten into the coin die, plugging up the first T in the word "Trust," making the motto seem to read "In God We Rust!"
There have been a lot of errors turning up on the state quarters, but the "struck through grease filled die" type may be the most common. Learn more about how these errors happen, what they look like, and how much they are worth in the first article of a regular series about interesting coins I buy.
Photo by Susan Headley