Conficker.C primed for April Fool's activation
 

Conficker has caused trouble for months since it appeared in late 2008, and a new variation of the worm is set to launch again in just over two weeks. The new "C" variant will be significantly harder for the security community to track, and could cause headaches for infected users as it's much more difficult to remove.

http://arstechnica.com/security/news...activation.ars