The late comedian George Carlin is being honored with a portrait at the Smithsonian Museum's National Portrait Gallery, to be unveiled today.

The museum's historians and curators selected three comedians to choose from - Carlin, Groucho Marx and Ellen DeGeneres - and the public chose Carlin in a vote on the website.

Carlin, who died in 2008, was known for his blunt and unapologetic approach to taboo subjects.

His "Seven Words You Can Never Say On Television" routine led to his 1972 arrest on obscenity charges and was part of a Supreme Court case in which the court affirmed the government's power to censor material on public airwaves.

Meantime, as the Smithsonian honors Carlin, the Library of Congress is adding 25 recordings to its National Recording Registry, including Johnny Mercer, The Doors, Sly and The Family Stone, Radiohead and Lauryn Hill.