Athens 2004 goes for the gold by offering a whopping 25 events, including classic Track and Field events (Long Jump, 100m dash, etc.), Aquatic events (four swim meets), Gymnastics, and more obtuse sideshow events like Horse Jumping and Skeet Shooting. It's a much more complete list than most past Olympic video games have offered.
But this is all marginalized pretty quickly when you consider that about half of those events require the exact same tired gameplay device that has been used in Olympic games since Konami's Track & Field first broke knuckles back in 1983: button-mashing. Smash X and Circle to run the 100m dash, the 200m dash, the 400 m dash, to throw the Javelin, to swim in all four swim events. Mash your way to victory in the Long Jump, the Gymnastic Vault, even Weightlifting. It's incredible that in twenty-one years, no one has come up with a better plan, because this is as annoying, boring and skill-less as it gets.