Where I live, you graduate high school after the 10th grade board exam and then you do 11th and 12th grades after which you take another set of exams. The board exams are taken in February for most curricula from our country. However, I'm taking an international level curriculum (IGCSEs), which can be taken in May or in November. If we took them in May '15, we wouldn't get the results in time to get admissions to our new schools (most people change schools after 10th), so we did two subjects in May '14 and we're doing the other six in October and November '14. After that, we're basically out of school until our new schools start (sometime next year in June, most likely). So those of us who are doing the IGCSEs have holidays for ~6 months. Our batch (both IGCSE and local curriculum) graduates in February of next year, so basically we're having our board exams earlier to avoid complications with admissions.
TL;DR busy preparing for exams from the end of the month 'til November, after which ~6 months of vacation
~Deadly