'Gwupigrubynudny' means in polish 'stupid-fat-boring'.
The closing scene was filmed on Ivenho Beacons, on an extremely harsh winters day.
The school football match scene was filmed in an actual school in Walthamstow, London, England. Child extras were rounded up from nearby theatre groups. Two children were picked from each, and it was considered a great honor to be allowed to take part in filming.