"You're not usually this caring and considerate... what are you up to, Rainbow Dash?"
Spike's birthday has been declared an official state holiday of the Crystal Empire, and Rainbow Dash has the most awesome of presents in mind... and a Sonic Rainboom is only the beginning...
Takes place during Season 4, in between "Simple Ways" and "Testing, Testing, 1, 2, 3". Mildly AU, since for story purposes Spike finds out he's a hero in the Crystal Empire prior to "Equestria Games". Otherwise, this is canon-compatible.