Of all the things we are inclined to take for granted, the weary exhalation of air that is commonly referred to as a "sigh" easily tops our list (other things that we take for granted: our mother's love and Laser Pink Floyd at the planetarium on Saturday nights). But not Instructables member mkontop, however: this guy is clearly fascinated by the theory, practice, and ramifications of sighing, even going so far as to build a device that not only monitors his breathing and measures his sighing, but then goes on to store the corresponding amount of exhaled air in a box nearby. To what end, you ask? Perhaps you can ask Marcel Duchamp next time he's in town. Hit that read link to build one for yourself, but not before peeping that video after the break.