1. Insanely good product.
Dark Sky is an app that tells you about the weather. But... lots of apps tell you about the weather! Here's why Dark Sky is different:
It uses the geo-locater on your phone alongside weather radars to determine the weather in your exact location at this exact moment. So, instead of having to open up an app to see how the weather looks, you'll get truly helpful push notifications throughout the day that say things like "Downpour starting in 11 minutes" or "Light drizzle ending in 3 minutes". It's awesome.
The app costs $3.99, which I happily paid more than 3 years ago, and I've never looked back. I hardly ever even open the app, but I use it via push notifications every day. I'd advise you to check it out.