A "nail test" (Nagelprobe) sounds like it should involve a hammer and result in something getting broken. However, nail refers here to the physiological kind, which is German is also called "Nagel." It is said that the ever-so-popular expression refers to an old drinking tradition: After a toast, the merrymakers would turn the empty glass over onto their thumb. A dry thumbnail was proof that every drop had been drunk -- the theoretical goal. A moist thumbnail naturally meant try, try again! Though you'll rarely see Germans with glasses on their thumbs in pubs today, the term "Nagelprobe" is in common use -- frequently in the realm of politics -- and refers to a particularly challenging trial. As for Bavaria's former Premier Guenther Beckstein (pictured), he'll have to drink up if he wants to pass the old-fashioned "Nagelprobe." But considering that he lost his job earlier this year when he party, the CSU, failed to get an absolute majority, it seems he couldn't exactly pass the contemporary "Nagelprobe."