Upcycling is my favorite. Using something old for something better. We've found that something as worthless as Capri Sun blocks make the best big blocks. Not only that, but they have words and letters on them, and it gets you extra points for environmental print.
EVERY child should have a set of blocks. And there is no excuse when the blocks are so free!
The wooden blocks are more popular, but the Capri Sun blocks make frequent appearances.
They make great tunnels.
This looks suspiciously like a coffin... but I think it's just fun to enclose someone.
Castle making with both kinds of blocks.