Keep Calm and Carry On was a propaganda poster produced by the British government in 1939 during the beginning of the Second World War, intended to raise the morale of the British public in the event of invasion. Seeing only limited distribution, it was little known. The poster was rediscovered in 2000 and has been re-issued by a number of private sector companies, and used as the decorative theme for a range of other products. The poster and its parodies have appeared in almost every channel open to graphic design and graphical parody, ranging from the political messages to cute slogans. There are only two known surviving examples of the poster outside government archives. (Wikipedia)
So...here goes my "Keep Calm and..." gallery. Collected them from all over the internet (...mostly tumblr).