4th Edition D&D
The huge news at GenCon that came out is that the 4th Edition of D&D is coming out in May 2008. (Player's Handbook in May, Monster Manual in June, Dungeon Master's Guide in July). I didn't attend the announcement presentation (links here), but seeing the YouTube video of it I don't think it was done well. I could have given a much better speech than those guys. And the information was vague. I liked the ideas they talked about, but I want details!
I did get some interesting info from Rob Heinsoo (the 4th edition lead designer) about 4th edition. I was doing the Dungeon Delve demo at the Wizards of the Coast booth so I could get my black-robed Raistlin promo repaint mini, and they were short-staffed, so Rob subbed in to DM. Now this was a 3.5 edition demo, but Rob had been playing 4th edition for quite some time so I was able to gather a few tidbits from rules slip-ups he made or vague allusions he made: for example, rogues will have some way for their sneak attack ability to affect plants in 4th edition. He said to the person playing the rogue something like, "Wouldn't it be nice if your signature ability could be used in this fight?" Unfortunately, I can't really remember anything else specific.
UPDATE: I do remember one more thing: instead of players having to ask the DM how injured a monster looks all the time, there are official "states". If a creature is reduced to half hit points or less, it is "bloodied" and everyone can tell that it in that state. This goes for characters, too, of course. Some monsters have abilities that get triggered by being in the "bloodied" state or by others going into that state. Gnolls, for example, go into a frenzy if anyone nearby is bloodied.