What is St. Jude known best for?

St. Jude is known as the saint of hopeless causes. His name was frequently confused with the traitor Judas. When people were told to pray to St. Jude they often responded "That would be a hopeless cause!" thinking of Judas rather that Jude. So, the title stuck and St. Jude became the patron saint of hopeless causes and a saint of last resort for many Christians.