How to be informed of click on Play button? Can play state be accessed?

Hi, I'm just getting my feet wet in terms of MS plugin development. Thank you to everyone for all of the great resources available -- the documentation, the library of plugins, and everyone commenting here!

I was wondering whether either is possible:
- can a plugin register itself (as an event listener) when the Play button is pressed? Or more generally, when the Play "state" is toggled?
- is it possible to access the current "play" state i.e. know whether MS is currently playing or not?

Thank you in advance! I may chime with more questions :-)