Sort of like Stevepit's idea or you could leave an anonymous note unless of course you're the only neighbor. You could also complain to the landlord if you are continually awakened by their over zealous activities. You only need to say that your neighbors are very noisy and constantly wake you up in the middle of the night. Keep a record of every-time you are awakened, so you have some type of verification to give the landlord. However, if it is only an occasional happening, as unpleasant as it may be, just deal with it.