So, for grins and giggles, last time my local gaming group met I brought copies of the first three commercially published roleplaying games for show and tell: Original Dungeons and Dragons; Empire of the Petal Throne; and Tunnels and Trolls. (The order of the last two is debatable.)
The release of 4E and the choruses of “It's not real D&D” had actually interested me in looking back at what D&D really was, so I bought PDFs of Original D&D (from RPGNow) and its supplements and printed them all out and bound them in 8.5”x5” pamphlets, in more or less the original form factor.
Listening to the Whartson Hall Gamers playing Empire of the Petal Throne from the RPGMP3 Community Podcast rekindled my interesting in Tékumel, so I bought a PDF of it from RPGNow and printed it. (This really drove home how much bigger and better presented EPT was than OD&D. Also, how even less Politically Correct it was.)
And T&T had been in my thoughts since Ron Edwards' wrote a series of reports on his T&T game. I played T&T a bit in my youth, so I already had a copy of it, the 5th edition, so I let that stand in for the 1st edition, a not unreasonable bit of flexibility, since T&T seems to have changed much less over five editions than D&D did over 4.5 or so.
(Later: I can't imagine why I didn't bring my copy of FFE/QLI's republication of the original Traveller Books 1, 2, and 3 along, and have one of the first SF RPGs too!)