Of course, most of you know of bumpmapping. Not many high-end games nowadays that doesn't take advantage of it. Its big advantage is that is allows us to recreate lost surface details at a per-pixel level.
Its big dissadvantage also comes from its advantage. Because it works by simulating details from a lighting's point of view, the effect fails when the lighting environment is almost constant or when you are looking at a mesh from up-close. The reality is that a truely bumped surface would not only alter the light as it would with a bumpmap but would also occlude other parts of its geometry.
Reading on one of my common lookouts (GameDev), i'v notived a discussion on parallax mapping. In essence, the idea is to not only apply bumpmapping to your mesh but also skew the texture UV's of you mesh to simulate the parallax effect which would be caused by real 3D bumps on an object. What is amazing is that for only a few extra lines of shader code, it can produce some quite interesting results.
Here is a link for an article by Terry Welsh on the subject of Parallax Mapping.
What surprises me most is that this idea just came up and i havn't yet heard that anyone is using it!!!