You don't have to be programming a game to find the gems like the ones for rendering and geometry useful.
To get a feel for the quality of the gems I looked at the gem on "The Parallel Transport Frame". I'd encountered this problem myself when trying to get VRML extrusions to work properly. VRML extrusions use Frenet frames so fail when the curve has an inflection. I came up with the same solution as the one described in this gem, and I'm sure many others have reinvented this particular wheel. The gem accurately describes the problem and solution and if I'd had it while I was messing with VRML extrusions it would have saved me some trouble.