Sharing files across devices -- even when you're on the same network -- is often a pain. Apple has a decent solution with AirDrop, but that's not helpful if you're swapping files between Windows and Mac. ShareDrop is a web-based solution that works across platforms.
ShareDrop works in Chrome, Opera and Firefox. Just open up the ShareDrop page on two computers on the same network and you can then drag a file into your web browser to share it. That's it. It's simple, fast, and it doesn't require storing files on an external server to work.