DIY drawer organizer project ~ 48 wood laths super-cheap at Home Depot, & the store will cut them for you. So simple it's not even really a tutorial :-) Would also work to make a shadow box to display small items.
Would be fun kid hideout space! Awesome dog kennel under the stairs design idea. If you want an indoor dog house, utilizing the space under the stairs for a cozy, attractive and practical space for dogs is a good idea! I love this design.