Our flight home from Paris leaves us with a very long layover in London Heathrow: like 10 hours long (really!). We used frequent flyer miles for our tickets so choices were limited, and since the tickets were (almost) free I can't complain too much.
Still, 10 hours in any airport is a long, long time (and then we get on a long flight - fortunately it's a non-stop). It's been years since I went through Heathrow, and I never spent any time there.
Can anyone suggest good things to do there to pass the time there?