The Huntington Library and Gardens is a wonderful museum housed in the mansion built in 1919 by Henry and Arabella Huntington.  The museum recently underwent an extensive remodel, to enhance the visitor's experience observing the museum's large collection including  

"18th century British and French art, and on American art ranging from the early 18th to the early 20th century.  Other objects of the same period round out the collection including French paintings, French and British sculpture, tapestries, furniture, porcelain, and silver, and British drawings and watercolors.  The collections have continued to grow, both by gift and purchase, particularly in the area of American art.  Temporary art exhibitions include shows derived substantially from The Huntington’s collections, as well as traveling exhibits from other museums throughout the United States and abroad.  The Huntington is world-renowned as home to Gainsborough’s The Blue Boy and Lawrence’s Pinkie."

The Huntington Library and Gardens offers a free day, on the first Thursday of every month with advanced tickets. 

Parking is also free daily.

Its extensive grounds (over 120 acres) offer interesting botanical specimens and tranqil open spaces to wander through.  Large open lawns are a fun place for children to run and tumble, while shady paths make for a pleasant stroll out of the heat of the day.

The Armory Center for the Arts presents a gallery of contemporary art exhibits, as well as offers art education and studio classes in the visual arts.  Admission is free.  Unique works of art and accessible and informative staff make this a great place to visit in Pasadena.