CeBIT is an annual event taking place in Hannover, Germany. Usually, about 300000 (sic!) people visit this fair, which is dubbed the world's biggest IT expo.
The address of the fairground is "Messegelände, 30521 Hannover".
For next year, please have a look at the CfP and submit GNOME-related stuff, e.g. news from the GNOME community, or talks about new code.
If registered with Linux New Media AG, Free Software projects (such as GNOME) can get a stand of varying size. If you happen to be able to organise many people helping with the booth, you can get probably get very big booths as well. So plan ahead!
The Linux New Media AG wants you to staff the booth all week long from the very opening to the very end. All the time. So make sure you have enough peoplepower to actually do that.
Details for the events can be found here: