Version 1.0 of the 1st edition Dungeons & Dragons-inspired game OSRIC is available for download from its official web site.

Also known as the "Old School Reference & Index Compilation", the game attempts to captured that 1st edition feel using a combination of the non-copyrightable portions of the original rule set with the terminology from the d20 SRD.

Why do it? The developers themselves say it best:

The reason for going back to square one and restating the underlying rules is simple. It allows old school publishers (both commercial and fans) to reference the rules set forth in this document without making reference to any protected trademark. (This document is trademarked, but the use of the trademark is permitted under the terms of the OSRIC™ open license --- see below). By using this document in tandem with the Open Game License ("OGL") of WOTC, a publisher should be able to create products for old-school fantasy gaming and clearly refer to this particular rule set without violating the terms of the OGL.

I looked through an earlier incarnation of the rules, and everything you'd expect to be there is there -- the classes, the spells, the magic items, and -- perhaps most importantly -- that old school feel. I don't know if my group will ever run it (it would be fun to try a one shot, just for old time's sake) but it's nice to know it's there.

You can learn more and download the rules by visiting the OSRIC web site: http://www.knights-n-knaves.com/osric