I finally spent the 60 seconds it took to find the keyboard shortcut for Smart Tags, like the paste options and auto format tags that show up in office. Ready for it...?
This will expand the smart tag so that you can use the keyboard (arrow, enter, esc) to pick the option.
Here's the info from MS on the keyboard shortcuts.
One other tidbit... If you need to bring up the context menu, but your keyboard doesn't have the button for it, you can use Shift-F10.