We've already seen magnets and clips used in products that allow cyclists to do away with their frame-mounted water bottle cage. The problem with both systems is that they require users to stick with a brand-specific bottle. With Torq Athletic Gear's new SnapFlask, however, riders can use any bottle they want.
SnapFlask is pretty simple. Two neodymium magnets are mounted on the bike's existing bottle cage bosses using stainless steel bolts, and a steel base plate is attached to the bottle using a Velcro strap. The magnets engage the plate, keeping it (and the bottle) snugly in place until it's purposefully tugged off by the user.
The strap presumably does a decent job at holding onto the bottle, although it might be a good idea to put a strip of grippy inner tube rubber in between the two.
Torq is currently raising production funds for the SnapFlask, on Kickstarter. A pledge of US$25 will currently get you a model with a stainless steel plate, when and if they're ready to go. If you'd prefer one with a magnet-equipped carbon fiber plate, that'll run you $50.