my nephews quite often spends night at my huse, and they have their own room here, with a bunk bed. Most nights i put deakon who's 2 to bed before Xavier, who's 4.5, and that works, but when they both go to bed together i find they just play... when they wont settle, i let them take a book each to bed, and they're allowed to read. I find this works better than forcing them to sleep (eg no light ) i just leave a lamp with a low wattage globe in, and i find within about 30 wins, they're alseep. And i dont have to get up every 2 mins!

Good luck, its a tedious task...