The Lower Columbia Time Bank is a local manifestation of an intriguing national trend. Chelsea Gorrows May 1 story is a good description.
Modern technology in the form of the organization's website (www.locotimebank.org) facilitates an ancient system of trading our own skills for those of others. In a Medieval village, the blacksmith might have made a gate for the town scribe with an understanding that the scribe would write letters on behalf of the wagon driver, who hauled a load of iron to the smith. This works fine in a small setting without too many participants.
Nowadays, time banking offers the potential of allowing far more complex multiparty trades of good deeds. It is a way to build new alliances and connections, while bypassing the government-run money and tax system.
These time banks require broad-based participation and buy-in. Give it a try.