So I went to school very like Hogwarts - Castle, houses, the whole shebang - and one thing we had that I qssume hogwarts has as well but isn't in the books is prize giving day. The first book tells about a trophy room which has more than 3 tropheys in (house cup, quidditch cup and special services to the school), and even assuming that some are interschool trophies, there are almost certainly some annual parenial trophies. I think it's it's detail Rowling forgot she included.

So prize giving is a day, usually after a-level results come out when the school invites students who did well in exams or were nominated by teachers to come back for a dinner and a bit of a shindig with parents.
Prizes would be things like
First year of the year
Best gcse results (owls)
Best A level results (newts)
Best sportsman
Best artist (separate from subject art/music prize)
An annual prize for each subject, nominated by the teacher
Annual prize for Best in House by the house head

There were also awards for just being nice/popular with teachers.

The awards were usually named after notable teachers or students.
The P.J.Leqhy award for English or Bishop Quinn Trostan House prize for example.

Might be something for every August?