I had to make a solar oven(cooker)for a science project in school.It was a simple one time use thing but all i used was a lunch box and lined the inside and the lid with aluminum foil, then I propped the lid up with a straw on both sides then i faced it towards the sun and left it sit for like 20-30 min(i cooked a hot dog)The hot dog turned out really good! i said that i was going to show my dad how to make one for the canoeing trips we go on instead of having to buy propane all the time and he tried it and it worked, it was fun!!
Thank you Jason for sharing your solar oven experiences, it sounds like you made a convert out of your Dad with your homemade solar oven.
You might also be interested in taking a look at these great solar cooker designs as well.