"Action" is a placeholder word for any
noun (or sometimes
verb) that is clear by context but which the speaker is too
lazy to remember.
As in:
- "Let's fire up the action at the spot." equals "Let's go to Hank's house and play Starcraft."
- "Let's do some lunch action." equals "Let's go to lunch."
The "lunch action" construct is a way of making lunch (and you) sound
hip and
with it because you're
down with "action."