Daddy's home! Jump on him!

Ninis cure for jetlag:
1) Find sleeping patient. Aaah, he looks peaceful, doesn't he? It won't last...
2) Carefully position your smaller, shrieking child on his chest. When the patients eyes spring open, this child will then claw at his face. With luck she will also have soiled her nappy, so that the pungent aroma so close to his nose will help to bring him around.
3) In case he still seems sleepy, allow (well, OK, encourage) your larger, faster moving child to leap from a standing start on the bed onto his stomach and/or testicles.
4) Feign sympathy in the most appallingly unconvincing manner (for maximum effect, try and stare out of the window as you do this, thus making it plain you are thinking either about the weather, or possibly some gardening). You might also choose to mutter over your shoulder, in the quietest, mildest voice you can muster: "Don't do that, girls", while you check yourself out in the wardrobe mirror.
5) Cut across his howling and say "It's eight 'o' clock, are you getting up?"

Works every time.