He plays a pivotal role in many of the best episodes, and it's Frank who invented the wonderful holiday of Festivus, which may just be Seinfeld's most enduring legacy. Helen Seinfeld (Liz Sheridan ...

(Photo by Dennys/Getty Images) Actress Liz Sheridan, who played Helen in the hit television series “Seinfeld”, died in her sleep of natural causes early Friday morning in New York, her ...