Pokémon Liquid Crystal is definitely an amazing hack. If you haven't played HeartGold or SoulSilver before, then you should definitely give it a try. If you have, though, then you could still play it, but I'm not really sure if you'll be enjoying it as much. xD" Ruby Destiny series is also a must-try. Aside from these two, another hack you could play is Light Platinum. Played it before myself, and enjoyed each and every second of it. I might give it another run at some point in future.