Also forgot to add for options, allowed / disallowed user groups

I actually have a dirty implementation of this on lovinity.org that goes beyond just using codes for earning points. It can also be used for executing code for various things, say, for example, you can use a code to upgrade one's usergroup. Probably not going to release it at this time though because I am not sure of its security given it evals code typed into a catalogue field (but only admins would ever put entries in that catalogue anyway).