select a variety of napkins that match your party decor. premeasure your ribbon so you know exactly how long you want it.
A) leaving the napkin folded, cut through all the layers from the bottom to about 1/2 an inch from the top seam. make strips about 3/4" wide all the way across.
B) unfold the napkin, layout your piece of ribbon, and tape the ribbon to the napkin. then fold the napkin back over. repeat for the entire length of ribbon.
Then you hang it up and say "TA-DA!"
This is literally the easiest thing ever and it added such a colorful punch to the backyard party.