The Original Xbox backward compatiblity on Xbox One goes live today.
Here is a list of the titles:
Star Wars: Knights of the Old Republic
Ninja Gaiden Black
Crimson Skies: High Road to Revenge
Fuzion Frenzy
Prince of Persia: The Sands of Time
Psychonauts
Dead to Rights
Black
Grabbed by the Ghoulies
Sid Meier’s Pirates!
Red Faction II
BloodRayne 2
The King of Fighters Neowave
I'm going to try this out when I get home from work.