Game Sprockets were a neat concept for the time -- bundle a bunch of useful tools for building games into a set of standard system libraries. A response of sorts to ActiveX. Perhaps my favorite feature was the standardized control remapping interface -- many games were still rolling their own user interfaces for this, or simply not allowing controls to be remapped.

Unfortunately, not very many games ended up using Sprockets. (And the framework never made into Mac OS X at all.) Shame.