This past week on CSI 3 victims all had green blood and no there
were no aliens involved. When I saw the previews from the previous
week I knew that the probable cause was going to be drug related
and I turned out to be right. The producers of the show decided to
call the drug "Thiocyte" (there is no such drug) probably fearing
lawsuits but they did get the right type of drug - migraine medication.
Sumatriptan (Imitrex) is thus far the only suspected drug to cause this
effect (not yet proven to cause this but very suspect and only in
daily or above average doses).

http://www.cbc.ca/canada/story/2007/06/08/health-green-blood.html

You can google Sumatriptan green blood and get a lot of hits now on
the growing number of cases (surgical).

It's the sulfur that swaps out with the iron in the blood that turns
the blood green. After stopping the drug the blood turns red again.

It was sort of fun to watch the show and be right about it before
the show even began but I'm also sure I'm not the only medical person
who was watching who had it figured out before they had gotten very
far into the show.

It was fun to see the Mythbusters guys show up but I wish they had
had a bigger role - bring them back!