Watermelon, of course!
No food signifies summertime like fresh juicy watermelon, dripping from your chin and streaking down to your elbows. I mean on the kids... yeah, the kids are messy _wink, wink_.
Think of the napkin-needed potential of even this small bowl:
Just screams juicy and messy doesn't it?!
Almost as much as Popsicles at the lake: