Wow. Just simply wow. Check this out right now. Author Kevin Crawford has released a free .PDF of his amazing retroclone, Stars Without Number, which is not released under the OGl and thusly does not claim any direct compatability with any system... but it is pretty much compatible with any pre-3e edition of D&D with minimal changes. The coolest thing is that this looks suspiciously like B/X crossed with Traveller.
No, I lied. The coolest thing is the equipment list. No, the world building tips. No, the easy to read layout and the concise but evocative writing.
I am going to hork the equipment list and make a few random tables out of it so that new starting characters in my Mutant Future campaign can have something cooler than a short sword to kill things with at 1st level!