I'm sure Ford Prefect will be there to buy you all a round.
You know, the Maya calendar doesn't actually end on 21st, it just goes onto the next b'ak'tun, we're on the twelfth now, we'll be on the thirteenth after 'doomsday', and then onto the fourteenth on 26th March 2407. For the twentieth B'ak'tun it resets to zero and adds a Piktun, that will be on 13th October 4772 (I bet it's a Friday too). It doesn't even end there, twenty Piktun is a Kalabtun, twenty Kalabtun is a K'inchiltun, and twenty K'inchiltun is an Alautun. That means it'll take over 63 million more years to get to one Alautun and over a trillion years for the calender to reset to zero!
Wikipedia, it's fantastic.