Sony's rootkit DRM.
Need proof? Here's an interesting piece by Declan McCullagh, in which he points out that (a) it was probably illegal for Sony to install the software on users' computers, and (b) it's probably illegal for users to uninstall the software once it's there.
Sometimes the absurdity just reaches right out and whacks you.
[UPDATE on 12 Nov 2005: Microsoft's anti-malware team announces that it will remove Sony's rootkit from infected computers. It would be interesting to sit in on some meetings in Japan this coming week.]