There are Contests, completing the Pokedex, Latios is roaming the wild (Latias if you have Sapphire) and of course you can migrate your Pokemon to Diamond, Pearl or Platinum and start an entirely new game. Hope this helps! :D
Start getting all the Pokemon or train your 6 Pokemon to level 100 and try the battle tower.
YES, YOU DUMMY!(after you defeat the Pokemon League and get the Ruby/Sapphire.)
On Ever Grande City
The Pokemon League
If you're referring to Pokemon Ruby, Sapphire or Emerald then; Once you've defeated the Pokemon League, go to Steven's house in Mossdeep City and select the Pokeball on the table, you now have a Level 5 Beldum.
you only have to beat the elite 4 on Pokemon fire red not ruby
Through victory road.
skill
Groudon. That's it.
You can enter the Pokemon League once you've defeated all eight gyms and have the gym badges.
You get your first Pokemon, then warp back there after beating the Pokemon league.
defeat the pokemon league