Raid/Instance Cooldown Window

Ah, this is because the Social tab was removed from the main list of menus on the bottom of the screen and consolidated to another area.

To open up the Social Tab, you can use the default hot key 'O' or click the little man icon right above your chat box. On the bottom, you'll see four tabs - 'Friends,' 'Who,' 'Chat,' and 'Raid.' Click on Raid, and in the top right corner, you'll see a button called 'Raid Info.' Clicking on there will bring up the list of all your current raid and instance cool-downs.