When you are listening to Music on your iPhone or iPod touch the device replaces the usual clock and date from the lockscreen with Music controls. This allows the users to easily perform useful actions related to the Music app such as playing or pausing the currently playing song, changing volume as well as jumping to the next or previous song. However very few people know that in iOS 8 and iOS 7 you can press the home button to show the big clock and date, even when the music is playing.
This is useful in situations when you need a bigger version of the clock (since a small one already appears in the status bar) or want to check the date for today. To bring the clock all you have to do is press the home button once. You can return to the original state of the lockscreen and get the Music controls back by pressing the home button once again.
This is a neat feature of iOS lockscreen and certainly one of those that can be really handy at times. This works on the stock Music app as well as every third party music app that shows the Music controls on the lockscreen.