Minecraft Thread X: In the jungle, the mighty jungle, the ... SSSSSSSS

[The Bushranger]

Hostile mobs (skellingtons, zombles, Nice Everything-seeking creepers) will spawn if the light level is 7 or lower. (Honey BadgerSlime doesn't care but only spawns down low.) A torch gives off light level 14; so spacing torches appropriately (they can be up to 12 blocks apart, but usually less looks better) will stop spawns. Glowstone will work as well, but redstone torches will not.

However, one thing to keep in mind is that the Xbox version of Minecraft is based on the PC version's Beta 1.6.6...which means the Two Block Rule is in effect - and, based on your description of what happened, I suspect this is the problem. Basically, if you place a bed against an outside wall, it doesn't matter how lit up your room is - monsters can glitch-spawn through the wall (so to speak) ("They're coming out of the walls!!"), which will wake you up and, if the mob in question is a creeper, result in Something Happening to your Nice Everything. The solution here is not to place your bed against a wall - you must have all of the bed at least two blocks away from a block which is valid for monster spawning (i.e., one block for the wall, one block of air, then the bed = no monsters; bed touching wall = SSSS).

This was fixed in the PC version later (you can even sleep safely completely outside if you go to sleep before spawns start in the evening); I presume as the Xbox version is developed it'll be fixed there too, but for now, remember, bed against wall is bad.