The Sagan picture shirts are on white or light colour only. Otherwise choose any colour you want. Hit the shirt to get the colour options.
I might pull the picture shirts shortly, depending on copyright issues, so if you want one get in right now!
These T-shirts are all Carl Sagan themed. Later, if I feel inspired, I may do e.g. a twee "Russell's Teapot" and an all-action "Bullshit Force!" (perhaps based on the A-Team, only with Russell, Sagan, Dawkins, and Randi as Mr T) version.