Pokémon HeartGold Version Easter eggs

Get to the Sinjoh Ruins and get Dialga,Palkia,or Girantina!
To get to the Sinjoh Ruins,you have to get Arceus. Have only Arceus in your team,and if you have all 26 Unown's,go to the Unown Research Center in the Ruins Of Alph.A man will run out and say he feels something is about to happen and he takes you inside the ruins.You will be transported to the Sinjoh Ruins and go to the house in the eastern part.Talk to Cynthia and she'll take you to a building and will say to choose a pokemon.(Dialga,Palkia,or Girantina.)It will show a cut scene of Arceus making an egg appear,and you get it.Eventually,it will hatch and you will have a lv.1 Dialga,Palkia,or Girantina!Happy cheating!