Mix strawberry jello according to package directions. Put in refrigerator just until thickened, about 1 1/2 hours.
If using a homemade Angel Food Cake, the cake must be thoroughly cooled before you slice it.
Slice cake horizontally as thin as you can, about 1/2" thick. (Don't panic if you break of the layers, you can just piece them together with the jello) Lay first layer, the top layer of the cake, back into your Angel food cake pan, cut side up.
Mix orange jello about 1 hour after you refrigerated the strawberry jello. Then refrigerate that.
Once the strawberry jello is thickened, spoon jello over the first layer of cake and return to refrigerator.
Start the lemon jello about 1 hour after you started the lemon jello.
When the orange jello is thickened, place the next layer of cake over top of the strawberry jello in the cake pan. Spoon orange jello over the second piece of cake and refrigerate.
Continue the process for all of the colors. Lemon, Lime, Blueberry, Black Cherry.
Hopefully, you will be out of cake, if not, you will have to remove the cherry jello from the refrigerator, you will be able to count how many pieces of cake you cut, to determine if you have to do this step.
Obviously, do this cake the day before you need it!
Use a sharp bread knife to cut through the angle food cake. Cut all the layers before you start layering the cake. That way, you will know how many colors you need, and if you need multiple layers of the same color.This cake has to be built in an Angel food cake pan.If you measure the dry jello, you could do half of the box at a time, then the jello will not get too set while waiting for the current layer to set.If, once the cake is cut, you only need one layer of a color, you are home free and can make the entire box.Now that they have come out with a blueberry jello, you may only need 1 layer of each color.Lay colors in the order of rainbow, namely, red, orange, yellow, green, blue, violet (use black cherry or grape for the violet layer.Leftovers last for 3-4 days. As the days progress the jello will leak water and the bottom layer of cake may get soggy.Drain additional water off of the plate daily.