Frequency did a really great Linux 1k recently. To the Road of the Ribbon is a classic labyrinth but (to my knowledge) for the first time with reflections and even a ribbon added. It fits in Linux at 1k nicely but is about 1240 bytes under windows, though xt95 made no attempt to make it smaller under windows, it was small enough under Linux. For some reason it was buggy on my ATi box so out of interest I converted the Linux assembler to C and ported to windows.
I couldn't quite get the code down to 1k using crinkler under windows (setup for windows is larger). Perhaps some jolly fellow can convert it back to asm? You can get my C version here, with a much compressed shader. Its around 1070 bytes using crinkler.
There are some nice tricks in this intro. I like the hi-res clock passed in through glColor4ubv:
t=timeGetTime();
glColor4ubv((unsigned char *)(&t));
and then in the shader (my version):
float w=dot(vec3(gl_Color),vec3(256/256,256,256*256))*.256;
The dot product was a great idea to get a hi-res clock, not sure if its original to Frequency but its very cool. I optimised the size a little by making the original vec3(1,256,65536) into the form above.