Ben Affleck's 10-Year-Old Son Takes Wheel of Lamborghini and Hits Car

Ben Affleck's 10-year-old just got into a little mischief ... by jumping into the driver's seat of a VERY expensive Lamborghini, and with the engine running he put it in reverse and it made contact with another car.

Ben and Jennifer Lopez went with Samuel Garner Affleck Sunday to 777 Exotics, a Bev Hills luxury car rental dealership. They were all looking at various cars when Ben let Samuel hop into the driver's seat of a yellow Lambo.

Seems Samuel or someone else had the engine running ... the boy put the Lambo in reverse and it seems that's when it made contact with the white BMW.

From the video, it seems the rear bumper on the passenger side of the Lambo made contact with the BMW's front wheel and possibly the fender.

It's hard to tell from the pics, but Sam jumped out of the Lambo and went to the back to inspect possible damage.

A rep for Ben tells TMZ ... there was no damage and everyone's ok.

An employee at 777 Exotics told us there was no accident and the cars were just parked really close together -- which is true -- but that doesn't explain why Samuel would get out and inspect the 2 vehicles.