According to Marriland.com on May 9th an event is starting and it is Darkrai. =) You can watch his site for new updates.
there will be a next event on pokemon black and white
As of April 26, 2012, the next Pokémon White event will be a Wi-Fi distribution of Sinnoh's Legendary Pokémon, Darkrai. It will begin on May 9, 2012.
Soon sometime in the summer of this year the phantom ruler z Pokemon movie will come out celebi is the event Pokemon in this movie when its out on DVD the event will begin! --- The Celebi event is going on now at GameStop! It runs until March 6th, the day Pokemon Black & White are released.
It's an event Pokemon
meloda is an event pokemon, the date of the event is unknown
event.
It is an event pokemon, the event for which has not been run yet.
It is an event Pokemon and currently unavailable.
You can only get it with an event.
There is not an event to get Keldo YET.
Event
It needs to be an event.