Grafica library
Every 4 years two main events in Germany coincide in time. The Oktoberfest takes place every year in Munich during the last two weeks of September and beginning of October. The German elections day (Bundestagswahl) happens every 4 year almost a the same time. I wonder how many Germans try to vote totally drunk after a whole day at the Oktoberfest...
The data was obtained from Google trends. Click near the points to display the labels.
For more details, check the source code or play with it at JSFiddle.