You know ... girl or boy ... with mint green walls ... I personally would go for a Bug's life theme.

Little catipillars, ants, ladybugs, frogs, leaves, praying mantis ... even some birds ... bees, moths, what you call the ones with the long wings that live in the water (darn pg brain) *think-think-think* .... .... hmmmm .... gosh .... DRAGONFLIES!!!!!

I have a 19 month old dd and she is CRAZY over worms and bugs

Just a suggestion

Also ... Jungle Book goes with green walls .... Fairies (if you have a girl) ... Daisies (I love daisies)