Swords into ploughshares
Or in this case, cannons into children's swings. The cannon in question was left behind by Nazi troops retreating from a Soviet village during WWII. From the ever-fascinating site englishrussia.
Speaking of whimsical uses for guns, our iron curtain comrades have also devised this little number. While the gun won't shoot (it's fake, duh) it'll sure get you loaded. And hey, as long as we're celebrating the intoxicating AK-47, take a detour to the Kalashnikov museum.