Ours (7,5,3) took over the forward cabin (sort of a v-berth but they're singles). We just put together a sterilite box of assorted toys: Barbie, littlest petshop etc. and they play for quite a while. N.B. no teeny parts or you'll be finding them in the bilge for years afterwards. With the oldest being 7 they're just doing imaginativ play and are not too interested in formal games unless we're doing the game with them.
As much as I hate it, I may break down and get a portable DVD player- but not yet.