I made our very own Lego Pinata using a regular box and 6 Crystal Light canisters. I filled the box with all of our goodies and then wrapped it with a solid color paper. Cole helped peel the paper off the canisters and then I cut them to just 1.5 inches tall. Cover them with solid paper and glue them on top of your box. I threaded a pipe cleaner through the top of the box so that we would have a way to hang it. 
Thanks for posting this Lego idea too Shannon! Yeah! My son wants a Lego pinata. Did the box break easily? What kind of box did you use?
I'm SO glad I found your site! This is an awesome idea and great DIY project! I'll be using a lot of your ideas for my son's lego party! thanks!