Take a bucket
Fill it with water
Add a good amount of good quality dish washing detergent
Take a fly swat
Dip the fly swat in the detergent water
Move the fly swat back and forth vigorously through the air
Watch the bubbles float and fly
This activity requires good supervision since it involves water in a bucket. You'll be amazed how many bubbles you get - some will be like dish washing water bubbles that land nearby and some will be big round bubbles that float way up into the sky.
Always remember to get the most bubbly fun you need to put the dishwashing detergent in after you've filled the bucket with water. If you put it in before the water, all your bubbles will be in the bucket and you may as well do the dishes!