Futuremark is discontinuing some of their older 3DMark Benchmarks, as such you can now download the Full Versions for free incl a usuable key.
Benchmarks include 3DMark 06 and everything below including PcMark 05 as well.
"These benchmarks are provided for entertainment only. They may not work with current operating systems and online services may have been retired. We recommend using the latest versions of 3DMark and PCMark to test modern hardware and devices. These benchmarks are no longer supported by Futuremark, however, companies that need information can contact our sales team for assistance. Individuals should visit our forums for help and advice from our community."
Have a browse at the now Free Benchmarks and keys here.