We live on the beautiful Oregon Coast so here is a fun idea for anyone who lives near a beach..... SAND VOLCANOES. The kids and I had the best time building two volcanoes out of sand and burying two red, plastic cups to the brim. We then added 1 Tbsp. of baking soda and a few drops of red food coloring to the cups. When we were ready for the "lava" we poured in 1/4 cup of vinegar. The mixture fizzes up and will spew out of the cup and down the sides of your sand volcanoes. Next time we do this (and it will be soon as my kids really enjoyed this) I am going to bury small, plastic pop bottles instead of plastic cups. Make sure you take your cups/bottles with you and leave your section of the beach cleaner than you found it!