5 hours in Shibuya area, Tokyo-things to do?

OK, spending 9 total hours in Tokyo, from landing in NRT(3pm) to taking off from HND(midnight). Middle of December if that matters.
I am taking my mom over there for her birthday forsushi. I am planning on heading to theShibuya metro station and going to a sushi restaurant there (one of thoseconveyor belt sushi places).
After that I have no plans. I did find a couple of beer pubs so we might go for a beer.
Between dinner and a couple of beers we could have 2 or 3hours of more time and I have no ideas of what else to do except walk aroundthe shops.
If anyone has been there and could throw out some ideasplease do.

Buddies did the same last year. Let me find out where they went and post again. They ordered some eats at a food court--vending machine pics and pay for ticket. Food appears at counter. Looked pretty interesting. Said it was tasty. I'm sure the people watch/walkabout will be fascinating.

My gang flew the opposite way so their experience was nothing to share. Sorry. Only recommendation from the primary was take the train into the city. BTW the train from NRT/HND takes about an hour.

Thanks for trying mrs767er, opposite way would not matter if they went to the Shibuya area. Many places to go in Tokyo and the chances they went to Shibuya are low, even though Shibuya is the metro station that has the busiest pedestrian crosswalk in the world, I think. Problem with the time we are going is it will be dark, will be arriving in the city right around sunset. I am sure I have the metro/train situation figured out from NRT and to HND, just looking for any recommendations in the Shibuya area, even restaurants, do not have to go to a conveyor belt sushi place, could be a sit down place, just want to take her to sushi.

Did you go yet? I got this notice thru TA:
The Tsukiji Market - Chuo - Reviews of The Tsukiji Market - TripAdvisor

Will not be in Tokyo in the morning to hit the fish market. If flights stay good should leave on Sunday morning and be home Monday afternoon. I also have my itinerary in the Shibuya area.

Sounds like a man with a plan. Kanpai!