Here are some links if you want to learn more about the currencies mentioned in the Currency Lab game’s Fact Book:

Bitcoin

http://www.theguardian.com/technology/2014/mar/18/history-of-bitcoin-hacks-alternative-currency

http://www.forbes.com/sites/andygreenberg/2013/10/02/end-of-the-silk-road-fbi-busts-the-webs-biggest-anonymous-drug-black-market/

Bangla-pesa

http://www.standardmedia.co.ke/business/article/2000104244/bangla-pesa-makes-huge-comeback-after-court-battle

Cubo Card

http://p2pfoundation.net/Fora_do_Eixo

Wir

http://p2pfoundation.net/WIR_Economic_Circle_Cooperative

Wörgl

http://www.lietaer.com/2010/03/the-worgl-experiment/

Terra

http://www.lietaer.com/2010/01/terra/

Dogecoin

http://www.businessinsider.com/what-is-dogecoin-2013-12

Frequent flier miles

http://www.economist.com/node/1109840

http://www.theguardian.com/money/2005/jan/08/business.theairlineindustry

Caslow

http://opencurrency.com/community-currencies-have-a-long-history/

Curitiba bus tokens

http://www.lietaer.com/2010/09/the-story-of-curitiba-in-brazil/

Time banks

http://www.yesmagazine.org/new-economy/time-banking-an-idea-whose-time-has-come

http://timebanks.org/more-about-timebanking/

Brixton Pound

http://brixtonpound.org/why-use-b-2/b-vision/

Palmas

http://imaginationforpeople.org/en/project/banco-palmas/

Gold stantard

http://en.wikipedia.org/wiki/Gold_standard