Sleep Cycle - Bio-alarm clock that wakes you up at optimal times based on your sleep patterns.
Spotify - Map shows when two people play same song at same time
SleepBot - SleepBot is a sleep tracking app available in Google Play and the Apple App Store.
Last.fm - The world's largest online music service. Listen online, find out more about your favourite artists, and get music recommendations, only at Last.fm
Sleep Time - Alarm Clock - Sleep Time provides insight into your sleep patterns. By tracking your level of movement throughout the night, Sleep Time generates customized sleep data in easy-to-read charts.
SoundCloud - Enjoy music & follow favourite artists