Homegrown Evolution: Time Banking:
So what is money but an abstract representation of misery, time spent doing things we'd all rather not be doing? How about an alternative? How about taking all of our hard earned capital away from the Wall Street types? Get ready for time banking.
With time banking, you get together with your local community members, friends and family and exchange hours rather than currency. Time Bank USA describes the concept succinctly:
'For every hour you spend doing something for someone in your community, you earn one Time Dollar. Then you have a Time Dollar to spend on having someone do something for you.'
Time banking isn't defined as barter, so you don't have to pay taxes on services or goods exchanged. And time banking is egalitarian--everyone's hours are valued equally--an hour of digging a ditch is the same as an hour of legal services, or acupunture or whatever.
The castle project has a lot of similar ideas, but ties it together with a shared purpose and an xp system to reward long term participation in the system with greater than zero-sum rewards.
Time currency, like dollar currency, may be an important component of the castle building model, and it might make sense to just use Time Bank directly, rather than try to replicate it.