Youtube-DJ - Mix YouTube songs together
Sampulator - Make (and record) beats on your keyboard
YOU.DJ - Mix SoundCloud music and Youtube videos live in your browser.
Splice Beat Maker - Make and share beats in your browser
Edjing - Discover edjing and edjing Pro, the most powerful DJ apps for music lovers! Mix on Android, Windows and iOS devices and record then share your DJ sets!
BlokDust - Join blocks together to build sounds with this web-based music making app.