Seraching for the Half Term Holy Grail....

Checking the EU school holidays is a very good suggestion. Google for 'eurydice school holidays' and pick out the 'Organisation of school time in Europe' result for a detailed report on the school term times and holidays in the EU.

The current report for 2010-11 holidays is at

http://eacea.ec.europa.eu/education/eurydice/documents/calendars/102en.pdf

but the actual URL will change each year. Looking through this, it's amazing just how holidays are spread out i.e. there's almost no week in the winter when some region of some country isn't on holiday, although the main Christmas, half-term and Easter periods are obviously the worst.