Try going to google.de, Google's German based engine, and you may see a page that looks like:
As of right now, it seems Google.de is offline. Why? I have no idea...
A quick check of the Google.de registration shows Google owns it, but doesn't show me a date of expire...
Danny first reported this at Search Engine Land.
Forum discussion at Search Engine Roundtable Forums.
Update: Appears to be back as of last night some time. Rumors are that the domain name changed ownership for a short period of time. Please see comments for some other ideas.
Update 2: The Register has more details on this story:
Goneo called us with the full story from its end. The google.de domain changed hand three times last night, a spokesman said. A request to take over the domain was placed with Goneo about a week ago. The firm automatically placed a request with German domain registry DENIC (the equivalent of Nominet), which put the request to Google's German provider. The provider did not respond in the first instance, and ignored a second approach from DENIC. According to procedure, DENIC then approved the request on Monday evening. Goneo became aware of the registration, and arranged with Google and DENIC to have it transferred back. Unfortunately, somebody else had made an application to register it too, through another domain company, which had also been ignored, so it was transferred to them first. Google finally took possession its German digs this morning.