In Prix Olympia 2004, SingPost won the award for the most original stamp issued for the Athens 2004 Olympics Summer Games (see page 2 of this document). The stamps are shown below, and there is a short write-up accompanying the stamps in the 2004 yearbook. The award was presented by the IOC to SingPost during the 2005 session.
In 2005 we have the stamps series on the 117th IOC (International Olympic Committee) itself. Personally I prefer the 2004 design to the 2005 ones. The 2005 ones look a bit commercial somehow. Well, wonder if there will be stamps design for the 2008 Olympics, and also the Youth Olympics in 2010? Should have I would think. Let's hope the designs are good.