Microsoft delivered a big batch of mobile happiness at its annual MIX developers' conference this morn, promising a host of major features including multitasking, background audio, push notifications and raw sensor data (not to mention over 1500 new APIs) in the next version of Windows Phone. Of course, it's one thing to tell you how pumped attending developers might be to bite into a nice juicy mango next month and another to see for yourself, so feast your eyes on the best of Windows Phone Next in the video above. Not bad, eh?Sean Hollister contributed to this report.