If you find yourself in Paris, the National Library has a great exhibit on JRR Tolkien [0] until February 16. Christopher Tolkien's work is heavily featured. It's fully translated in English (for once).

[0] https://www.bnf.fr/en/agenda/tolkien-journey-middle-earth

Pybossa (http://pybossa.com/) is a great (IMO) and FOSS alternative. NASA and CERN (amongst others) are using it. See some application examples here: http://crowdcrafting.org/

> "Based on volunteers not micro-payments"

It seems that this does not really help the original poster. Very interesting, nevertheless.