I found this idea here. I thought it would be a fun summertime activity.
First, cut the bottom off of a water bottle.
Then cover the end with an old dish cloth and secure it with a rubber band.
Now this is the fun part. Blow through the top of the water bottle (be careful to not suck in--yuck!) and out come the bubbles. I don't have the best pictures of the results. My daughter didn't want to blow in the bottle and I couldn't take a picture of myself doing it. She did have fun playing with the end result though. Check it out here for a better idea of what happens.