A 3D-printed version of the Paperfuge, based on ideas presented the following paper:
The thin adapter pieces fit around a 1.7ml microfuge tube, which then sits in the grooves in the model. Make sure that the centrifuge is balanced (i.e. use 2, 3, 4, or 6 tubes at once, arranged symmetrically).
Feed two pieces of <3mm rope (e.g. old shoe laces) into the holes, twist the ropes together, then pull and let go to create a forward/reverse centrifuge action.
For a single-direction hand-powered design, see thing:1807878
An audio analysis of my video suggests that this could be running at around 7,000 RPM (~100 samples per spin at 48kHz with four tubes).
Handfuge in Action