for the bench team we dont run any game tests but use synthetic tests like 3d mark and such.
games like crysis and f1 2010 (and many others) have them built in to the full game but im pretty sure you need the game as it uses the game files to run the timed demo, i could be wrong here as its not something i do often and i own those games to use the benchmarks so havent looked for a free version.
my sig is a link to many free benchmarks if your interested in joining the team
Yeah some publishers will release downloads early as a tester/teaser so potential customers can see if their rigs are up to it. (as well as seeing the eyecandy)