This isnt really a yopyo, its more like a ball on string, but you can stil do fun tricks with it.
I had the idea when I came across a really good Instructable about mini-yoyos, unfortientely, it was only a slidshow so I just invented my on kind. This is preatty fun, it haves the adventageof beeing hookd to a ring so the string won't fall off your finger. I'm sorry, my spelling might be very bad because Instructables letter check-up is down and my auto corrector is jamed to french.

Step 1: What You Will Need

You will need for this Instructable :
-string (always cut more then you think you will need, you can always trim it down)
-2 big buttons
-a very small button
-a glue gun
-a ring (not on image)

Step 2: Making Your Button Top

Take one of your big buttons and glue the small button in the center. When you glue your small coin, glue it on the flat side, it's easier to start with.Then, put some glue on the small button, put the string in the glue, and put the other button on top of it. Now all you have to do is hook your string to the ring, and your done! Now you can do tricks with them (my favorite is flicking it and then it will come back to you) or you can fiddle with it when your nervess.
Enjoy!