Max can't wait. He wants his tennis ball and he wants it now. He lets out a thunderous woof! "Oh, you want this?" teases his mama, Viviana Bojourno. "Well, here you go!" She hurls the ball. The four-year-old black English Labrador gives chase, snatches the fuzzy sphere, and turns it into a slobbering mess. His gal pal Tabitha, a two-year-old bull terrier, comes over and playfully paws Max's face. He gets up and runs after her. A black Lab puppy named J.J. careens into the two pooches. Even Shakes, a female golden retriever/chow mix with a sprained right paw, is having a grand old time at the latest pooch playpen to open in Miami-Dade County. Conveniently located on the east side of Biscayne Boulevard, four blocks north of 163rd Street, the Northeast Regional Dog Park sits on 1.67 acres divided into two sections for small and large hounds. As their canine companions frolic on the grass, mark territory around the fire hydrants, and run in circles, owners can sit and relax on wooden park benches and picnic tables dotted throughout the doggy area. Bojourno, an Aventura resident, loves Max's new playground. "The park is wonderful," she says. "It is so nice and safe." Just remember it opens at dawn and closes at dusk. And if you take your barking best friend to East Greynolds on the weekend, expect to pay a $5 entrance fee.