Thermodo

Ever wish your mobile device could give you a more accurate reading of the current temperature than it gets from the weather app du jour? So did the folks behind Thermodo. This itty-bitty sensor plugs into your headphone jack, working with a dedicated app to give you an accurate reading of the surrounding temperature, with not even an Internet connection required. When it's not in use, you can plug it into the included keychain holder, giving you one more thing to add to your janitor-like chain of trinkets.