Blacklisting wouldn't really help as the spammers tend to go through many other sites as well. A couple of solutions were presented here, Recent Mass Football Spam. Most active mods on SE and the staff are aware of the problem as it's SE wide and it has happened in the past.
Previously, I used to drop all spam accounts into one master account and then ban ...
In the first instance we need to try and remove the tag from the system. In this case the way to do this would be to delete the questions as they are really so far off topic there's no way they could be edited into shape.
Then once that's done we can request the blacklist.