A few weeks ago I saw a nice printable geneva wheel posted on Thingiverse (http://www.thingiverse.com/thing:1642) and later I saw a wooden geneva wheel which was lasercut (http://www.thingiverse.com/thing:1616) with the DXF files as well). You can find a nice visual picture of how it works at Wikipedia (http://en.wikipedia.org/wiki/Geneva_wheel). Yesterday I saw them again and thought “Why do I not make one myself??!”. So I powered up my cnc machine and used the DXF files and converted them to g-code. About an hour later:
Now I got my own Geneva wheel, and it works smoothly!