'Twins' (1988)

Kudos to Ivan Reitman and the four screenwriters behind 'Twins.' After all, not only were they the first people to cast Arnold Schwarzenegger in an actual comedy ("actual" since 'Commando' and 'Running Man' are downright hilarious), but they realized that sometimes the easiet way to make an audience laugh is by resorting to jokes about height. Making Arnold play a perfect genetic specimen doesn't hurt either.