On June 23, adCenter will be upgrading to expand negative keyword management to the campaign level.*

During this upgrade, adCenter will be temporarily unavailable for up to 14 hours, starting at 10:00 A.M. Pacific Time. Your keywords and ads will continue to run during this time. After this upgrade, reporting will be delayed for up to 24 hours. To see when your data was last updated, check the timestamp on the bottom of adCenter Reporting tab.

some more cool stuff they have done recently too :

Editing your keywords in bulk and previewing ads
Creating multiple account performance reports and new information on misspelled keywords
Importing campaigns from other search advertising programs

DaveN