So for my exams I also have to make and write a paper on a Geometry Shader written in ShaderModel4.0 for HLSL. My original idea was to do a grass shader because...they seem kinda fun. Well it didn't work out so well and I had technical problems that I still don't know what was causing them.
So, instead of grass rendering I decided to make things explode! So I wrote this shader (with some help from my teacher to try and get some more velocity on the pieces when the explosion starts) in the last little bit and I think after playing with the equations a bit I finally have a decent start on this. I am still going to try and make the pieces have some more variance in speed but it's a work in progress.
Above, is the link to the video I took inside FXComposer2 where I wrote the shader. As I said, it's the first (good) iteration and I'm gonna try to tweak to be even a bit better than current but, that being said, there it is.
I'll also be posting the paper on it later (going to write it tonight/now-ish) and some snippets from the shader itself as there really isn't that much to go on when searching for Geometry shader help/tutorials (that I found atleast for DirectX)