It seems like each iteration of iOS comes with a handful of new Siri tricks, and iOS 8 is no different. Wired points out two new Siri features you might have missed: the ability to rate songs and identify them.
The rating songs feature is pretty straightforward. When you're listening to a song from your music library, say "Rate this song five (or whatever number) stars", and Siri will rate it for you. This comes in handy when you're making smart playlists based on ratings. You can also now ask Siri to identify songs playing around you by asking "What song is playing?" Siri will listen to the music around you and use Shazam to try and identify it.