I think you can redeem it here: http://iam8bit.com/dayofthedevs
Ah,I thought it was for the Humble DOTD Bundle. Maybe someone else will be interested. Thank you though.
You welcome. Sorry about the confusion.
If someone is still in doubt, this code gets you a VIP pass for the Day of the Devs (in San Francisco) and a 20% off cupon at the ima8bit store, so if you aren't in the US (like me) the key is pretty useless.