What's the story behind the name of the SOS (Son of Strike) debugger extension?

Jason Zander's blog post explains it perfectly:

The original name of the CLR team (chosen by team founder and former Microsoft Distinguished Engineer Mike Toutonghi) was "Lighting". Larry Sullivan's dev team created an ntsd extension dll to help facilitate the bootstrapping of v1.0. We called it strike.dll (get it? "Lightning Strike"? yeah, I know, ba'dump bum). PSS really needed this in order to give us information back to the team when it was time to debug nasty stress failures, which are almost always done with the Windows debugger stack. But we didn't want to hand out our full strike.dll, because it contained some "dangerous" commands that if you really didn't have our source code could cause you confusion and pain (even to other Microsoft teams). So I pushed the team to create "Son of Strike" (Simon from our dev takes credit/blame for this), and we shipped it with the product starting with Everett (aka V1.1).

Also, I had heard of the CLR being referred to as "COM+ 2.0" before, but apparently it's had a few names in its time (from here):

The CLR runtime lives in a DLL called MSCOREE.DLL, which stands for Microsoft Common Object Runtime Execution Engine. "Common Object Runtime," or COR, is one of the many names this technology has had during its lifetime. Others include Next Generation Windows Services (NGWS), the Universal Runtime (URT), Lightning, COM+, and COM+ 2.0

This was discussed in a Scott Hanselman podcast with Tess Ferrandez a while back. It derives from an internal codename used early in the .NET platform. More info in the show transcript.