The Pilot G-2 pen that I (and many others) use is extremely susceptible to ink flow problems if dropped. So I came up with this centrifuge to deal with low ink flow problems.
Depending on your luck, you either end up with a restored pen, or more often than not, a leaking pen. But it's worth a try.
A PF M-motor powers the centrifuge. Theoretically it should spin at 880 rpm, but I think the actual value is closer to 700. The damaged pen refill is placed in on of those small containers. In the other container is a counterweight. Then the centrifuge is turned on.
Centrifugal force pushes the ink out, but this is a gradual process so we'll have to estimate the time needed.
Other than functioning as a centrifuge, I have experimented by adding curved blades (taken from a Technic model) to make a fan. It works great but maybe I'll build a better Lego fan in the future. It doesn't move enough air.
Here's the short video: http://www.youtube.com/watch?v=yQrEARkC9Uc