Cake sales
Mufti Day (£1 each to wear own clothes rather than uniform)
Put the teachers in the stocks and throw wet sponges at them, £1 a go (perhaps for the Summer Term, at Sports Day ...)
Run a beer and Pimms and soft drink stall at rugby matches, sports days, etc.
Hold a Quiz Night
Hold a race night (video'd races)
Murder Mystery Night (if you're in Surrey, I can put you onto a good thing)
Ladies Shopping evening - stallholders pay a set fee or 10% of takings. The mums get a glass of bubbly free on arrival and crisps, etc, and pay a small entry fee. It is good to have an eyebrow person on the stalls.
Guess which baby photo was which teacher all those years ago, £1 a go. Put the photos in plastic though.
The baby photo thing also works within classes, £1 a go, 25 in a class, 8 classes is £200.
Skool Disco for parents - sounds of the seventies and eighties, school uniform to be worn. Pay bar and a burger van - needn't be expensive. Prize for best 'uniform'.
Sponsored run / trampoline bounce / etc. Smaller times / distances for younger pupils.
I do too much of these things ...