Earplugs are definitely a simple solution, but have the drawback of not being highly visible to people around you. When I need to concentrate, I wear my big Se

Earplugs are definitely a simple solution, but have the drawback of not being highly visible to people around you. When I need to concentrate, I wear my big Sennheiser headphones - often not even plugged into an audio source. They are very comfortable for long periods, block out most of the noise, and (best of all) they send a clear "do not disturb" message to anyone thinking of interrupting.