Have You Found Any Of those "Other" 100 APIs ?
iPod . When you are playing a song. You just swipe from right to left to return to the previous screen. You could play a song from any playlist and swipe and it will take you to the main playlist. If you go to Artist , then an album and the "now playing" botton is there, you can swipe to return to the previous screen as well.
Post any of those APIs that Apple did not announce.