Here's what you need:
Sponges (I got a pack of 10 at the Dollar Store)
Plastic cable zip ties (mine were 4" ones I had left over from something else)
Water and a bucket or bowl
Here's what to do:
1. Take two sponges and cut them into long strips. Ours were about 3x5", and we were able to cut 4 long strips out of each. The kids (ages 4,6 and 7) could easily do this on their own with their kids' scissors.
2. Gather the strips together in a bundle with ends fairly even. Use a zip tie to cinch them in the middle and pull tight. I helped the kids fasten and cinch the zip ties (and used my teeth to pull it really tight ;) ) Trim the excess off from the zip tie and you're good to go.
We filled buckets with water, went into the backyard and had fun. They enjoyed throwing them into the air or just squeezing the soaked spongeballs over their heads. The spongeballs are soft enough that kids can throw them at each other in a waterfight (although one of mine usually ends up whining & crying within minutes if they get squirted or splashed by their brother or sister *rolls eyes* )
Having fun squeezing her spongeball over her head.