Start by filling two aluminum cans almost full of water and put them in the freezer (remember to remove any paper before doing this).
Next pick any pattern you like, or in my case just freehand it, since this was a quick project to keep the kids busy for a bit anyways! Take a nail and a hammer and nail holes to make your pattern in the can. The ice keeps the can from denting or folding under the pressure.
I highly recommend holding this freezing cold can between your bare feet. It felt fabulous! (Just in case you didn't pick up on the sarcasm in that...note now that I was being saracastic and please do not follow my example)
Once you are done nailing your pattern leave out in the hot sun until all the ice melts. You may need to hammer the bottom back in if it popped out due to the freezing.
Once all the ice is gone dry it very well! On the outside! Do NOT stick your hand in the can - the nail holes are extremely sharp! My husband found this out the hard way when I was busy and asked him to please dry the cans.
Next get out some paint and have at it! Again if you want a 4th of July do red, white or blue with star patterns or fireworks perhaps. For fall time or Halloween do a pumpkin shape with orange and black paint...you get the idea.
But remember this was a project for me to keep the kids busy and entertained so they just went at it with all kinds of colors!