One of the cool projects I've worked on this summer was this Ionic Thruster. After seeing the original idea on Make Magazine by Alexander Reifsnyder, I was amazed to see it work so I decided to build my own version!
To make use of the tools I had available I decided to build the entire structure using 3D printing. This way not only would be a more simple build but it would also be easily replicable. I already did a full article about this project on eLab Hackerspace's blog, but I'm going to summarize it here anyway.