Oblivion is going for $4.99 on steam today which includes knights of the 9 and shivering isles expansion. Pretty dang good deal if you ask me. $6.25 for game of the year edition which includes all the dlc.
Link:
http://store.steampowered.com/app/22330/
Link:
http://store.steampowered.com/app/22330/