Day 5: Today was a day trip to Osaka.
We bought the Osaka Kaiyu pass from the metro station which gave us a ticket to the aquarium, plus unlimited access to the metro (non-JR) trains. The pass worked out to be well worth it.
The Osaka Kaiyukan aquarium has a number of tanks with seals, dolphins, whale sharks (!), Rays, mola-mola, and some reef displays. I personally enjoyed it as I like watching sea life, but overall the place was packed with school kids on tours. (This seemed to be a common theme with all kid-friendly attractions on weekdays. Apparently children in Japan spend a lot of time on school tours :) )
The Tempozan ferris wheel was simply something we did because it was right beside the aquarium - it had nice views of Osaka from the top.. a short 15 min ride.
We also visited the Osaka castle. Unlike Himeji castle, this is a reconstructed castle, so not an original, but still makes for good pictures.
The evening was spent at Dotombori, a bright neighborhood beside the canal, watching the crazy neon signs, the running Glico man, and trying out all the food.