I have a habit of 'listening' to movie while surfing or reading. I found out this method accidentally with the free touchplayer.

1. Open touchplayer, tap a movie TWICE, it will open 2 cards of the movie
2. Slide up to cards mode, audio of movie will still run
3. Kill one of the movie that is not in sync with the sound, usually it's the one in the middle
4. Now you can do other things, I have tried ebook, surfing, app catalog, mosaic even sparkle hd

note: must tap twice, if only once when you slide up the audio will stop.

great feature. Not in ipad or android.