These are some monkey fists that I made for use as Christmas tree ornaments. I used cord that I found at Walmart and used ping pong balls for the fists' centers.

It's easier and faster to learn the monkey fist when they're made larger(at least for me, YMMV). So if you want to learn, you might try it first with larger diameter rope/cord and use a ping pong ball, golf ball, racquetball, or tennis ball for the center until you get the hang of it.

 It took me one hour to make these five monkey fists, but making a smaller one with paracord or smaller diameter cord, using several turns, and adding a sinnet, twist, or cobra stitch could take an hour or more to make just one.