You may know the Humble Indie Pack 2, which is a set of crossplatform indie video games. There's one game in the bundle that doesn't offer a 64bit build and therefore it fails to load.
It's called Braid and that's what you get when you try to run it:
$ ./braid
./braid: error while loading shared libraries: libGL.so.1: cannot open shared object file: No such file or directory
Of course the 64bit libs for OpenGL and the propitiatory nvidia drivers are installed, but the game asks for the 32bit ones, at least to my understanding. I do know that why can install 32bit libraries on a 64 bit linux system (we do that for the sake of crappy Adobe Flash), but I don't know where to find these libs (searching the repo with keywords like .i586 or ia32 led me nowhere).
so, any ideas?