The Crimean regional government in the Ukraine plans to hold a referendum, to leave Ukraine and join the Russian Federation, amongst its predominantly Russian-speaking population. The Russian parliament has voiced its over-whelming support for the idea.
Gary Kasparov, former world chess champion and member of the Russian opposition, points out that the same principle could apply to Kaliningrad.
Germany should adopt this law & offer referendum to Kaliningrad (Königsberg!) to rejoin Germany. I'd bet on result!
— Garry Kasparov (@Kasparov63) March 7, 2014
Geographically isolated from the rest of Russia, Kaliningrad — formerly known as Königsberg — was part of Germany (East Prussia) until annexed by Josef Stalin at the end of WWII.