As first mentioned in Eric's thread, a Darkrai event is now active on wi-fi. The details of the event are as follows.
Darkrai: Level 50
Ability: Bad Dreams
Hold Item: Enigma Berry
The only thing special 'bout it is the Enigma berry (where the **** is mah Custap game freak... ?), which is only obtainable via Dream World; not that it's guaranteed to be released in the DW. And hey, it's a Darkrai. No special moves, but ya might as well get it. I know I will be.