A long time ago, there was a canadian gaming site called ca-boom. One day they posted the rules for a deathmatch style game played with a standard deck of cards, and they named it Deckmatch. I thought it was really cool, bookmarked it, and then kind of forgot about it.
I remembered it sometime later and thought it would be really cool to make real cards for it. Magic: The Gathering style with icons, a nice image, and the card info all right there. Would certainly make the game easier to play and understand. In fact, I still might do that. But at the time I went in search of the rules and my bookmark was a dead end. The site had gone under. Google searches for "Deckmatch" had a lot of hits, but they were all blogs that simply linked to the original page (that doesn't exist). I believe I was able to scrape up a copy of the rules using the Internet Archive, but that took quite a lot of digging.
I tend to check out BoardGameGeek, a site about board games. They had Deckmatch listed, but no rules. I tried to upload the rules but was rejected because of copyrights. I wasn't the author, and it did make use of id softwares IP. Bummer. I still had it listed as a game I "own", and had several PMs from people asking for the rules...which I uploaded and linked them to. Recently an admin at BGG PM'ed me about the game since they were going to delete it since there was zero info available. I told him pretty much what I told you and linked him to the rules I uploaded once more. Haven't heard back, but the entry on the site remains...so hopefully it doesnt get removed.
Well, I'm going to save those rules, damnit. I made a Google Pages page with all the original rules, check it out
here. I posted a link to it in the BGG forum for the game, so hopefully people see it. I would love to get in contact with the authors, maybe edit the rules ro make them slightly more generic so we don't step on ids toes, and then release the rules under a Creative Commons license. My dream would be to create a site where people can download cards with full art like I said before.