Before having kids, I despised dealing with the cardboard boxes that came with every UPS delivery. Now that I'm a parent, good cardboard is as good as gold.
One of our favorites we've seen is this colorful castle. The architects? Christiane Lemieux's kids. (Yes, THAT Christiane, the founder of DwellStudio). We love how the castle interconnects, but our favorite has to be the colored masking tape. The children really used it to great effect. For more photos and tips on how to create one of your own, check out Built By Kids.
(Image: Christaine Lemieux via Built By Kids)


Sprout Side Table
This is FANTASTIC!!!! What a great idea. My problem with cardboard boxes is that they start to look junky (I know, I should get over it) after awhile and painting them is fun but hard to do in winter time -- I LOVE the neon zing of this tape! Fabulous!
This reminds me of my favorite new baby gift from www.bluemanateeboxes.com! Not only can you give board book favorites to a new (or slightly older) little one, but the box is designed to be reused and made into some fun creation, and you get some great building materials by way of packing noodles.