My plan is to get a foundation of globals out that can work for any game, and then add on a specific package of globals tailored to White Wolf World of Darkness games (for which I intend to use SGP's stat system, because it's a great piece of infrastructure), and that'll include things like +time. It'd be a simple thing from there to pick and choose something like SGP's RP pack for code that doesn't apply to every game, but is useful for certain games, and once you have mushcron and +time, birthdays are trivial.
The thing that actually got me onto the idea of doing this was time code. I started a project something like 6 or 7 years ago to do a set of astronomy code for moon phases, realistic sunrise and sunset times that change through the year, along with various events like the Perseids, transits of Venus and Mercury, etc. About half of that got done before I decided I should try to do my +time with a different ratio for day and night, like the system that Masquerade had. I failed horribly, and have been assured by several mathematician friends that what I'm trying to do is impossible without sequestering myself in a monastery devoted to both Sir Isaac Newton and Leibniz, and meditating very hard on the calculus. Which is funny, because I know other places have done it, and I'm missing something.
So I guess the point is that yeah, I can do that, and if anyone has code for variable day and night ratios please pass it along. ;)
--Stephen/Soylent (just woke up, and is kind of groggy)