New wi-fi event: obtain Latias or Latios!
Pokemon HeartGold & SoulSilver — 29 July, 2010
Starting this Saturday, July 31st and running until August 27th is a new wi-fi event to obtain the Enigma Stone item in HeartGold/SoulSilver.
If you take it to Pewter City Museum you can get it revived into a Soul Dew, which will make either Latios or Latias appear, depending on your version. HeartGold gets Latios, SoulSilver gets Latias.