I remember my cousin got castle greyskull. I had a couple of action figures like He-man with Battlecat, Ju jitsu, Man at arms and Skeletor. Good ol times!
Skeletors castle was neat. It had a microphone which distorted your voice, MUAHAHAHA!! It didn't sound high pitched as Skeletor in the TV series though. Now THAT would be awesome!
The entrance in CG could be used as the slot for the cartridges? And everytime you powered up the NES it could play "HE Man and the power of greyskullll"