Sodium bicarbonate (or baking soda) is a naturally occurring component of the mineral (or salt) known as Natron that is found in hot springs and other places.  Unfortunately the stuff at the store is produced artificially with sodium carbonate (washing soda) and carbon dioxide, but it is still non-toxic and natural.  Even the ancient Egyptians used natron as a cleanser or soap.

Baking soda can be mixed with cream of tartar to leaven bread instead of using baking powder. 

It is an antacid that can be mixed with water to relieve acid indigestion and heartburn.

I use baking soda to brush my teeth.  In a hurry I just pour some on my damp toothbrush, although you could mix it with some tea tree oil and a bit of water and keep it in a jar as a paste as well.  

When I run out of my current shampoo... I am going to go shampoo free.  You simply mix a tablespoon of baking soda in enough water to make a paste, and massage gently into your whole scalp (the massage is important).  I have really thick hair so it might take more.   Rinse out and then apply apple cider vinegar to the ends of your hair, and then rinse.  This is supposed to make your hair really icky and oily for a short while but your scalp soon adjusts and stops producing so much oil.  

Now I don't use antiperspirant anymore, because it's unhealthy and wasteful and all of that.  But I still have body odor so what do I do?  I use baking soda the same way people use baby powder.  It works best before you get sweaty, and I obviously don't want to stink, but I wonder why our society can't tolerate anyone who doesn't smell minty or flowery? 

And finally, if you need some tv-free entertainment for your kids, put a bit of water and baking soda in a bottle and pour some vinegar in and watch it foam.  Or you could do the whole volcano project thing and color it red too, but no matter what it's still fun.  The bigger the foam, the better.