Android: Join is a unique file sharing app that lets you share audio and photo files in real time with a single tap. It's awesome for sharing slideshows on your friends' devices, or just sharing your new favourite song.
Just open the application and click Create, then select the files you want to share. When the other devices are ready, their owners just tap "Join" to see what you're looking at, or hear what you're playing. You can control what they see from the master device, including swiping through photos.
Join doesn't require WiFi Hotspots, 3G or 4G networks to use it. Your friends have to have the app installed to use it, but it's free in the Google Play Store.
Join [Google Play]