First off, *thank you* to GiantMicrobes for making Mad Cow. I was really hoping for that one--my sister works in Agricultural Econ, so now she can have Mad Cow for Christmas so it can sit on her computer staring menacingly.
Sounds like a lot of the ones I'd like to see have already been mentioned. The T4 should be neat!
(Malaria) A classic Calamity.
(Chicken Pox) Come on, every kid should have one!
I think they've already got a lot of great ones, though.