RPGaDay #12 Oldest RPG Still Played/Read

For a fella that doesn't role-play anymore, my options are surely limited. 

I could easily cop to Call of Cthulhu, but I'm not playing 1st or 2nd edition, and while edition 6.1.5124123 x pi is still similar, even the adventures I'm running are late 80's at the earliest.

That leaves the answer to today's question to be Top Secret.

Back in the day, I owned all of the 2nd Edition Top Secret/SI rules and supplements, but never played a game of it.  In fact, the only time I knew anyone running a game was when my friend Scott ran it at Lehicon IV. 

Perusing my copy here, there's all the trademarks of a TSR game not called D&D.  Random tables, poor editing, and samples of combat that don't quite make sense.   But the percentile system is calling to me as a basis for my Gnomish Space Marine game.  I can even adapt all the outdated tech to something a bit more futuristic without too many hassles.    The only thing I would need to scrap is the hand-to-hand system, which requires to attack declarations per turn as well as one defense.  It probably simulates competing styles and spy movie combat well, but if the PCs want to down and dirty, I'll make my version a bit quicker.