Miniscule, but mighty powerful, the Withings Smart Activity Tracker will monitor your heart-rate while measuring such things as strides run, steps taken and calories burned. Its Bluetooth enabled and will allow you to keep track of your results via the company's very own app. The touchscreen makes it easy to use on the go and the battery will last for a whopping two weeks, which is probably longer than you'll honor that new gym membership. This thing's a pretty cool incentive to do so at least.