This takes a bit of anticipation and will amuse you for a few minutes. Work out the lat and long of the point directly opposite you on the other side of the world. Enter it on the legs page and then , as you overfly your selected position, hit direct to XYZ, hit enter and watch what the aircraft tries to do! It has 360 options if you get it right and does the most unexpected things!
(maybe you need to deselect LNAV before you do it!)
Good luck and happy landings.