Want to know what do I do at Intel? Obviously all details are secret, but generally, as a Graphics Software Engineer, I code graphics driver for our GPU. What does this software do? When you write a game these days, you usually use some game engine, but I'm sure you know that on a lower level, everything ends up as a bunch of textured 3D triangles rendered with hardware acceleration by the GPU. To render them, the engine uses one of standard graphics APIs. On Windows it can be DirectX or OpenGL, on Linux and Mac it is OpenGL, on mobile platforms it is OpenGL ES. On the other side, there are many hardware manufacturers - like NVIDIA, AMD, Intel or Imagination Technologies - that make discrete or embedded GPUs. These chips have different capabilities and instruction sets. So graphics driver is needed to translate calls to API (like IDirect3DDevice9::DrawIndexedPrimitive) and shader code to form specific to the hardware.
Want to know more? Intel recently published documentation of the GPU from the new Ivy Bridge processor - see this news. You can find this documentation on intellinuxgraphics.org website. It consists of more than 2000 pages in 17 PDF files. For example, in the last volume (Volume 4 Part 3) you can see how instructions of our programmable execution units look like. They are quite powerful :)