The Stardust-NExt spacecraft did a swing-by of the Earth today (miss us by 10,000 km) to line itself up for a pass of Comet Temple-1 on Feb. 14, 2011. This spacecraft is the one that passed through Comet Wild-2's tail and collected dust on it's aero-gel paddle. It then dropped off the samples which returned to Earth. The paddle and capsule are now in the Smithsonian with the other milestones of flight including the Wright Brother's flyer.
The Deep Impact probe crashed into (yes, on purpose!) Comet Temple-1 on July 3, 2005 and blasted a big hole in it. So now Stardust has been send back to check it out. The question is, how big is the hole? Could you fit a stadium in it? A mountain? Or will there be enough dirt from the $4 billion Seattle Viaduct tunnel plan to fill the hole?
Time to start an office betting pool to see who comes the closest. But when you ask your coworkers of your plan, they will probably look at you funny and say "Wha? Comet? Huh? What the heck are you talking about? Is the mothership behind the comet?" Never mind.... just crawl back to your cubicle, they will forget about it soon enough.