The next Global Service Jam will take place on the weekend of the 7th of March, 2014. That's the 7, 8, 9 of March in most countries.
(In countries with Thu-Fri-Sat weekends, it will be the 6, 7, 8 of March. For Wed-Thu-Fri weekends, it's the the 5, 6, 7 of March.)
Whenever your weekend is, it will be one to remember! See you there!