On a Virgin Australia flight they had a little "bar" area which was basically just an open standing area where you could chat with other passengers...next to an open liquor cabinet. The booze was probably not great for jetlag but I found a couple hours of standing and chatting was a great way to break up the trip and get blood flowing a bit.

Ever flown with a child? Grab a kid and walk up and down the aisle with them. Don't have a kid, just walk up and down the aisle anyways. People might look at you funny, but who cares.

We recently had made a transatlantic flight with our two very small children.... it was actually relaxing when, at some random point, they just fell asleep and we could sit for a while instead of moving all the time, also walking throught the plane just as you described.