Train my future lv 100 pokemon, egg move breed, or imagine I have pet Eevees that I can understand and talk to (in my head, of course) and take with me everywhere.
I usually re-battle my favorite gym leaders (like Jasmine and Erika). Back in the DPP days, I would go to the contests.
I do that but instead of contests I do the Pokéathlon, hoping to get to the secret room.
HG rules! I sometimes defeat Gym Leaders too. Mainly Jasmine, only to show off my own Steel-Types
How can anyone have nothiing to do when there are 646 Pokemon to EV Train and raise to level 100? Surely there are few people who managed to do this since March outside Japan and September last year inside Japan (and those outside Japan with Japanese games).