In year 10, I lead a group of 60 students to overthrow the SRC. We stormed the science lab where the meeting was being held, and I took control for three hours, until the school demanded that the previous, unelected body be restored.
The SRC at my school was extremely involved with student affairs - especially when the Opposition group under my leadership took up issues of OH&S, bringing in WorkCover and groups like that, and standing up to the school on disciplinary issues for certain students.
I think the biggest issue we had was about using student funds to donate to charity, or to spend improving conditions for students. Obviously we didn't have the money to do structural work to our school, but I believed that things like establishing a students' common room, installing ventilation in changerooms and toilets and other such things were more important than Stewart House and other such resume-pampering charities. Unfortunately, my opponents who held office (despite being in the minority) disagreed, so monies went all over the place.
In my belief, spending money on students would encourage the school and community to also contribute to make the school a better place for students - and after I graduated from high school, they eventually Did fix all the problems that I had highlighted.