I had exactly this (mine was called FairCoin) idea this weekend:
 https://bitcointalk.org/index.php?topic=343986.0

The crux for this to work is a ProofOfWork job that is hard for computers such as reCAPTCHAs but easy for humans; while easily verifiable by computers. Said puzzles need to allow the proofed integration of a list of transactions and a previous block's hash, to be chain-able and signing transactions.

Faircoin because:: This would provide both an adoption path and an income to the third world, where hard currencies are much valued, and human intellect work is under valued.

still thinking it through tho, any suggestions would be much appreciated.

(and instructions on how to exit from the newbie lockdown too...)

TIA,
h