Taken from a conversation on ACC.
FINALLY! I CAUGHT GROUDON!
I battled it with my Lv. 55 Dragonite and it took forever. I would just keep throwing balls at it after weaking it and it would always come out. I tried dusk balls, ultra balls, and so many different kinds of pokeballs. It was 4 moves away from a PP faint I'm not even joking. I finally got it to stay in a Timer Ball when it had 8 HP(out of 172).
Now if someone has HeartGold...