Mars must be final destination, no flybys. Must be working in some capacity upon arrival to Mars (can't blow up on the launch pad or fail to make it out of Earth orbit). It doesn't have to land successfully, just get to Mars, so orbiters count.
I will add more options if there are many missions planned closer to the transfer window date.

See http://www.clowder.net/hop/railroad/EMa.htm for more windows.

Earth to Mars

Hohmann Launch Windows