Who plays Clark Griswold in the 'National Lampoon's Vacation' films?

Which actor played George Bailey in 'It's a Wonderful Life'? In 'Elf' (2003), who plays Buddy the elf? In 'The Santa Clause' (1994), who plays Scott Calvin? In which film does Clark Griswold decorate his house with 25,000 lights? In 'Groundhog Day', in which town does Phil Connors get stuck reliving the same day? In 'The Shawshank Redemption', who plays Andy Dufresne? In 'The Shawshank Redemption', what is Red's real name? In 'Forrest Gump', what is the name of Forrest's shrimping company?