Even the so-called professionals can't always get it right. The Wizards' Chris Singleton may only be a rookie, but when you join the NBA, there is a certain level of expectations that come with getting drafted. After all, if you're able to, you shouldn't have a problem flushing down an easy dunk whenever you're asked. In addition, let's not forget professional bowler Josh Blanchard, who has gained notoriety for falling down after attempting to execute something he's probably done millions of times over. Now, let's take a look at these aforementioned mishaps and a couple other equally embarrassing stunts in this edition of Video: The 5 Biggest Sports Fails of the Weekend.