It's almost Halloween. You can juggle. Why not eyeballs?
Step 1: Materials
Step 2: Construct
I'm going to hand off responsibility for describing the manufacture of the balloon-clad flour balls to the KingOfRandom. Making squidgy juggling/stress balls from flour/rice and balloons is an oldie and a goodie, and he explains it fantastically well and has great tips to make it easy and relatively tidy. Watch the video.
The trick to make juggling eyeballs instead of ninja balls is a simple one - start with two black balloons and fill as per the video, with offset holes. You've made the pupil. Now make the iris with a color of your choice (doesn't matter which, as long as it's not white or black). Don't use the balloon neck hole, as it makes for a crazily dilated pupil, so I cut a smaller hole in the opposite side of the balloon. Position the hole anywhere on the ball that doesn't overlap either of the previous two holes. Finally, the white: place it so it forms a concentric ring over the previous hole. This is maybe the only slightly complicated part of the whole operation, and even it is easy.
Step 3: Decorate
Add a broken capillaries and an optic nerve by painting the ball with rubber cement, and arranging unraveled red yarn around the ball. Twirl the yarn together at the back and repaint it all with rubber cement. It gives the eyeballs a kind of gross texture and a slight yellowing effect, both of which seem entirely appropriate. Thanks to Penolopy Bulnick and audreyobscura for good advice on this step.
Gross out and/or amaze your audience with your juggling skills. Cover your own eyes with the juggling balls for a laugh. Happy Halloween!