They run for up to a year on a single battery, are weatherproof, and can be stuck just about anywhere you need access to temperature, humidity, light level, or plant growing information. They currently come in three different varieties -- scroll down to check out their individual features.
Climote gives precision temperature, humidity and light level information. Growmote tells you when your plants need watering, how much light they're getting and if frost is coming. Thermote sends you temperature information of an object it's pointed at: water, food, your pet gekco, or even your body!
We have a great app for iPhone and iPad with more apps on the way. If you run Linux or OSX, we have guides on using those too!