With the advent of the downloadable PDF, you can find just about any of the old RPG material online, and that's a good thing, too. If they had to print these things, I'm sure there would not be enough of a market for them, but just hosting a bunch of downloads is pretty cheap. Life is good in the Internet age. I've taken to going through the really old, classic D&D adventures. You can find just about any of them on http://www.paizo.com for about $5.
The last one I read, a couple of weeks ago, was not actually an adventure, but was the first D&D campaign setting, "The World of Greyhawk Fantasy Game Setting". Link: http://paizo.com/store/byCompany/w/wizardsOfTheCoast/byProductType/roleplayingGames/dungeonsDragons/aDAndD1/greyhawk/v5748btpy7meh&source=top
First of all, I definitely recommend this if you're a fan of this sort of thing at all; $5 for what was published as a deluxe box-set, with over a hundred pages of material, is definitely a good deal. The setting itself is cliche by now, but it was the first one, after all. It's a pseudo-medieval setting, dominated by human kingdoms in a pastiche of Dark Ages Europe. For a fantasy setting, the magic/elves/dragons aspect is pretty low key, being the exception rather than the rule. Oh sure, there's a kingdom ruled by an evil demi-god (Iuz), but for the most part it's more on the gritty, realistic side. Think Conan instead of Tolkien.
Beyond that I'll comment on two things; the first is that about 10 pages are dedicated to giving the statistics and abilities of the pantheon of Greyhawk Gods. Not the abilities that they confer to their followers or anything like that; the actual combat statistics of the Gods themselves! Considering how unlikely a typical campaign is to run into even one God in combat, I found this pretty humorous.
The other point of interest was a full 10 page treatise on generating random weather! I found this completely ridiculous, as you would expect; I didn't jot down the details but I do remember that something like every ten years you would expect an earthquake to wipe out every commoner (level 0) for hundreds of miles. But, unintentional comedy aside, I was also fascinated; the idea of making a (computer) RPG based on outdoor and overland travel has lodged itself in my head. I think it could be totally cool! Luckily I am busy enough with other projects and will never do anything about it.
Otherwise I've just filed away what I read, and hopefully some cool ideas will come from it into the game still known as "Untitled SENG Project". In any case, the campaign setting made for a good read.