Cardboard box oven
   
  Find a corrugated cardboard box about 2 in larger around than a cookie
  sheet.  Make sure it has an intact bottom and top "ears". Cut the
  bottom out all the way around and secure together with duct tape.
  Line the box inside and out with heavy duty aluminum foil and secure
  seams with duct tape.  Cut foil at the corners to free "ears". This
  is for venting. Line the lid with foil and secure seams with duct
  tape. Get four wire coat hangers and snip the hook off below the
  twist and straighten. Punch holes in the box about 6 in from the top,
  then push hanger wires thorough to make a rack. To Use: Start a
  charcoal fire with 6-8 briquettes in an old metal pie pan.  Place a
  piece of foil on the ground shiny side up. Put the pie pan on the
  foil and place the oven over the pie pan. Put your food to be baked
  on the rack and cover with the lid. If you have a meat thermometer,
  stick it into the box just below the rack. 6-8 briquettes should
  bring temp to 325-350. Add or take out to adjust temp. This should be
  done before starting to bake.