Soundproofing

[Wetzel]

Cheap easy things I have seen.

Place matress against walls.
Hang sheets from ceiling to floor in front of matress, makes the room look better and deadens sound some.
Hang a blanket from the ceiling like an upside down rug.
Mount noise making equipment - drums, speakers, jumping guitarists - on folded blankets or other 'squishy' material. This prevents sound from travling along the floor joists.

Sound is a wave, and moves best through a solid. It dosn't like to move from soild to air and back to solid. So when you have the drum on some plywood floating on a few thick blankets, the sound dosn't travel around your house nearly as much.

Read about the properties of sound in a physic book and you will prolly come up with some more ideas.

Wetzel