KNOX LEON AND VIVIENNE MARCHELINE JOLIE PITT

Brad takes Vivienne and Knox to a Hollywood park for some sliding and swinging (May 2).

Vivienne and Knox, almost three years old, attacked the slide and the swings at a Hollywood park while proud papa Pitt joined in, even taking pictures with his cell phone. Mom Angelina Jolie wasn't around but the kids didn't mind -- they had 100% of dad's attention!

Click here to see what Vivienne is wearing!