Here is a fun, easy weekend project you can do with your kids. When you are finished, you can enjoy a clay oven baked pizza together. Although the earthen clay oven takes more time to construct than the Yukon Stove, it is worth the effort since it can be used for baking.
Clay oven
Materials:

50lbs Kitty Litter ( clay litter, unscented)
100lbs Play Sand *Straw or Dry Grass
Dry Sticks ½ to ¾ inch diameter
Saplings 2 to 4 Feet long
Scrap or Old Fabric or wet newspaper
Shovel
Water
Tarp to mix your cob
1x8x18 Board to burn

How to Make Your Clay Oven:

First you want to find an area that is level and away from buildings and other combustibles.
Lay the dry sticks on the ground.

Mix some cob together about 1 shovel of sand and clay then place it on the sticks to make an insulation floor about 15 to 20 inches for the body of the oven and 10 to 12 inches wide for the mouth of the oven.

Next put the 1×8 board on top of the floor. This is going to burn instead of the saplings in base of the floor as it cures. It will also make the floor nice and level.

Now, with the saplings, you want to make a basket over the floor. Take a sapling and shove one end into the ground on one side of the floor then bend it so you can shove the other end into the ground on the other side of the floor. It is going to look like an arch.

Do the same thing with the next 6, or so, saplings, working your way around the sides.

At the back of the oven, shove a sapling in the ground and then weave the sapling through the top of the side saplings, and shove the end into the ground in the front of the oven continue doing that until the whole thing looks like an upside down basket.

Soak the kitty litter in just enough water for it to rest in, so it absorbs the water.

Mix up a bunch of cob on your tarp. Mix about 1 part kitty litter, to 2 parts sand and add just enough water so you can pick it and handle it. Make sure it is wet enough that you can spread it over your basket.
Place fabric or wet newspaper over the basket frame.

Pack your cob mixture over and around the frame, starting at the bottom and working your way up and over the top. Keep it up until you have a wall that is 2” to 3” thick.

Build a small fire inside the oven to dry it out, or cure it. This will take between 6 to 12 hours. Continue to feed the fire until the oven is completely dry.