1. Water Polo
They've got power plays like hockey, penalty shots like soccer, is named after a sport that involves horses, is in water, and includes headbutting while simultaneously treading to stay afloat. What's not to like?
Again a sport originally taken from horses to humans. Here's the lowdown via wiki:
The length of the race is usually 3,000 metres; junior and some masters events are 2,000 m, as women's events formerly were. The circuit has four ordinary barriers and one water jump. Over 3,000 m, each runner must clear a total of 28 ordinary barriers and seven water jumps. This entails seven complete laps after starting with a fraction of a lap run without barriers.
This 7 (women) or 10 (men) event sports shows the ancient Grecian heritage of the Olympics. Throwing Javelins, disks, or heavy iron balls, high and long jumping, hurdles, and old fashioned sprinting. The combination of events and skill sets that these athletes have is incredible.
Here is 2012 Heptathlon Gold Medalist (and poster girl of the London Olympic) Jessica Ennis. Her abs are ridiculous.
4. Cycling (Track: Team Pursuit and Sprint)
Get on a bike, be indoors, take some dangerous curves at super high speeds, and run neck and neck. Awesome sport. The Summer Olympics version of speed skating (one of my favorites from the Winter Olympics). Check out this video to watch some highlights.
Somewhat marred at this Olympics because teams are throwing games but still a wickedly awesome game. The reflexes are phenomenal. Again check out some video here from the 2008 Beijing mixed doubles final.