What I wanted to know, was how long it took you to travel somewhere when you ended up a DAY behind your starting time, effectively travelling back through time.
Always something that has intrigued me, I looked it up. The International Date Line lines up roughly (with some diversions around terrirtory) along the 180 degree line of longitude - starting between Russia and Alaska and making its way down through the Pacific between Tonga and Samoa. The map on the left shows this (click to enlarge).
So really the answer to my questions is this. If you flew from Tonga (on the Western side of the IDL) to Samoa (on the Eastern side) it takes two hours. But because you cross the IDL, you arrive 22 hours before you left.
If you flew at 7am this morning (GMT), your departure time (and date) would have been 8pm on Mon 23rd Feb in Tonga. Your arrival time would have been 10pm Sun 22nd Feb.
An easier way to remember it: if Sarah Palin was looking at Russia from her house she could see into the future, for Russia is a whole day ahead of her. Now if only she'd said that she could see the future, people might have elected her VP...
I need to get out more.