Here is  list of  codes! you can get cool stuff from it! But there are no codes for free memberships i am sorry about that :(

explorer - 100 gems
ngkidsrox - 1000 gems
discovery - 1000 gems

AJBAY - 3rd birthday cake
bemybuddy - 500 gems
AJHQ3000 - 500 gems
10million - 10million banner
ngexplorer - 1000 gems
drawing - 500 gems
hooot - 500 gems
alphas - 500 gems
kangaroo - 500 gems
koala - 500 gems
dolphin - 500gems