Justin Bieber -- Life's A Ball At The OC Fair

Justin Bieber strapped on the feed bag and headed down to the Orange County Fair with a few friends on Friday night.

The Biebs was spotted chowing down on funnel cake and playing carny games. It's unclear if he went home with any big stuffed animals, but the kid seems to be good at everything.

The yearly event -- fueled by more fried food than even the Honey Boo Boo clan can handle -- is a hot spot for teen girls, so we're guessing Justin felt right at home.

We gotta' say ... a lot has changed since he performed there 4 years ago.