In Popmundo there were various ways to get inspired. When you were inspired, you could write much more inspired songs than usually. It would be neat to have some sort of mechanic like this. It would also be "realistic," because, as anyone can trivially observe in the real world, you don't just sit down and practise writing songs until "practise makes perfect," and then you magically start churning out perfect song after song. You need inspiration.

Inspiration could be the result of some of these little events that pop up every now and again. It could be the result of a particularly good gig. It could be a result of a lot of things. If you're willing to go a bit PG-13, it could also be the (comedic) result of drugs, kind of like in the old Rockstar DOS game.