exchanges graphic start timebank guide how-to strategy vision ideas practices possibilities liability risk insurance introduction conference call potluck discussion q & a agenda core value group activities group games presentation orientation gifting gift economy coordinator call notes gift circle share economy skills abilities inventory member capacity needs tax irs cahn barter ruling missouri self-help school poverty poor community service money timedollar training timebanking economics co-production public services core economy mental health health criminal justice community well-being homecomer prison community weaver handout