DIY Weekly dry-erase board using a collage frame found at Walmart! Print days of week onto pretty paper, and put a different day into each section (behind glass). Write on glass with dry-erase markers.
Craft Stick Catapult - I made 4 of these in 5 minutes and they work great! You need craft sticks, 4 rubber bands, hot glue or tape, and a bottle cap (I cut apart an egg carton because I didn't have any bottle caps).