Things like mapping the volume button so that it changes the media volume instead of ringtone volume, and having full music controls, with album art, on the lockscreen. (neowin.net)
But the trouble is, they control notification and ringtone volume by default, and will only adjust media volume after a song or video has started playing. (android.gadgethacks.com)
Touch - disable mode intelligently uses the light sensor above the display to prevent the phone from unlocking itself in your pocket, and there are motion controls to reduce ringtone volume when picking up the phone, mute the ringer by laying it face - down, or automatically answer phone calls when placed against your ear. (pocketnow.com)