...in SPAAACE! is a game of cheesy sci-fi with a very nice points/bidding mechanic which may be a nice twist for those players fed up of being forced to run through the game master's whims; this is also not entirely serious but a lot of fun in a light-hearted whimsical sci-fi way.
Instant Game creates a scratch-built game by providing tables for Setting, Theme and Things. You then create characters to fit. There are so many cool things you can do with this that I would suggest you try it for yourself. To quote Bowman in 2001 "My God, it's full of stars." That's how much replayability you get with this.
OSRIC is a clone of old-school AD&D (1st edition) which remains faithful to the old warhorse without getting too bogged down in rules which made no sense and classes that didn't survive if you played them. It remains faithful to the original feel. Goblinoid Games produce other retro-clone RPGs such as Labyrinth Lord and GORE.
If you need fantasy RPG floorplans, go to Crooked Staff Productions as their stuff is impressive and very reasonably priced indeed.
For a collection of historic maps, look at David Rumsey's collection. Useful for Earth-based historic RPGs including certain modern or gothic-punk games.
Over at A Year of Frugal Gaming, The Frugal Challenge is on. If you've got a product that you want reviewing and it's going to get some re-use, send it over and you get a free review. As this is a site interested in getting value for product, you can show your chops.
Someone is blogging about free games and that person is Rob Lang. The Free RPG Blog does exactly what it says on the tin. And there is lots of free stuff. Usually amazingly high quality and Rob has a reviewer's eye for detail - plus he's walked the walk. Well worth your time.