I went to my leavers ball (I refuse to call it a prom and luckily that was the mantra at my school, I find 'prom' to be such an idiotic Americanism and hate the fact that it has infiltrated the UK education system) in Y11 with a group of friends, we had decided in advance that we were going to go as a group rather than couples and we really enjoyed ourselves as a result - one of my friends brought a pack of cards so we grabbed a table and played cards for a lot of the night. I saw it as a last chance to see a load of people who were going to college rather than 6th form as opposed to an angst ridden couples dancing night - by all means I danced but meh...
As for my 6th form leavers ball, I had just got a girlfriend so went with her but hung out at the tables for most of the night. I had turned 18 about a week earlier so spent a lot of the night drinking at the bar that had been provided for us.
Do I regret it? Not one bit because, despite me being there with people that I couldn't care less for I was also there with my friends, some of whom that was the last time that I saw them.
To the OP: I realise that you hate a lot of the people there but why not go with your 8-10 friends and have a laugh, you only ever get a Y11 leavers ball once in your life but you have your whole life (and at the very least the whole summer) to have mass all night gaming nights.