There are various sound canceling devices on the market. Some just generate 'white noise' to reduce the amount of outside noise which can be heard. These are often used in offices, etc.
You may also be able to find an 'active' sound canceling system which generates an inverse of the original sound which when combined act to cancel each other out. Such a system is often found in headphones and microphones but there may be larger devices available for whole rooms.
I don't know where you'll find such things but you could try stores like Sharper Image or others which special in hi-tech items.