Today is Museums of the Arroyo Day and it only happens once a year. What does that mean? It means that today only five museums located in Los Angeles and Pasadena open their doors — free of charge — from noon to 5. The 5 museums are The Gamble House, Heritage Square Museum, the Los Angeles Police Museum, the Lummis Home and Garden and the Pasadena Museum of History. For more information, click here.