Wikipedia is turning 10 on January 15 this year. And there are parties being held all over the world to celebrate it! If you live in a major city (or maybe even a smaller one), there are chances you'll find a party to attend.
If your city is not celebrating, you can organize it too, while getting some 'free merchandise' from them too!
Wikipedia has the list of all the cities and details on location and organizers on its site over here.
Unfortunately, I'm not going to be in any of the listed cities on the 15th of January.