Yes, lime green mickey head paint chip. They come from the Home Depot.
So if you see the initials HD thats Home Depot. If you see LGMHPC thats the mickey head paint chip. Check out some of the other sites that mention lime or lime green. It's the official unofficial color of the dis boards.
Yeah this is the link to the FAQ page about the secret green club: http://www.disboards.com/showpost.php?p=13460950&postcount=3232
It has some really really funny posts on there. Try and find DisUnc's post about his phone convo with his nephew. It made me literally laugh out loud. Then go and get your own LGMH (alien green is the official color) from home depot!!!