At the Castle school in Taunton, Somerset, desperate pupils covered the desk of teacher Julie Salter with messages urging her to let them join her, some sending faked letters from Hogwarts, and others artistic notes attached to cardboard owls and quidditch balls.
The school was one of more than a thousand to fill in forms in The TES and on a website to win seats at Ms Rowling's only public appearance.
This week the lucky 81 winning schools were sent their tickets for Thursday's event at the Albert Hall where the author will talk with Stephen Fry, answer children's questions, and read from her new book, Harry Potter and the Order of the Phoenix. Staff at the Castle secondary school applied for the event early after receiving a tip-off from two Year 11 pupils who run a Harry Potter fans' website.
Ms Salter, head of English, said she was delighted when she discovered the school had been selected and could send 50 students and five teachers.
When she told pupils that tickets would go to those who sent her the most persuasive messages, entries swiftly piled up on her desk.
"We had magic spells, messages attached to cardboard owls, quidditch balls made out of polystyrene," she said.
"One girl sent me an egg-box with hollow eggs containing riddles which led me to page numbers and specific words in the Potter books which revealed her name. The effect JK Rowling has had on the pupils here is incredible.
They've been trying to persuade me we should all wear Harry Potter glasses when we go on the coach."
Bookshops and libraries around the country will hold special events at midnight tonight to celebrate the launch of Harry Potter and the Order of the Phoenix. Details of the 766-page book have been shrouded in secrecy, but Ms Rowling has revealed that she has killed off a major character and was moved to tears when she wrote the death scene.
Schools which missed out on tickets for the Albert Hall event can watch it live on the internet by visiting www.bloomsbury.comharrypotteralberthall