The walls look so starkly grey. Might I recommend a different base color and maybe a stripe along the center of the walls, all the way around? That would go right along with Atra's suggestion, effectively placing wall trim at both the top and bottom. Maybe a bright pink or teal. That's bound to make the inhabitants want to close their eyes. :D
Willy Wonka would recommend vertical stripes, but I'm not a big fan of vertical stripes in a smaller room.