use a clear window screen.....crap i cant remember the link for it but there is a thread some where ....i think that the open squares on it is like 1/2" or so and you use alum window frame kit to .....well....make the frame...
eggcrate makes all the light go strait down....ewww
Guy is selling clear 1/4 inch stuff on here for cheap.I have ordered like 3 times from him now.The window screen kit and mesh works way better then egg crate.Also dont use the 1/2 inch stuff or will have this happen yet..........