In Michaelmas term there are the JCR Executive elections. These are the people that organise and run your Fresher’s week, Exrav, Christmas ball, socials and campaigns across the year. These are voluntary positions, voted on for the next calendar year to represent you on both a College and University level.
Each college is different but has something along the lines of:
Communications or publicity officers
Social and events officer
Every college has slightly different JCR positions up for grabs so keep an eye out around your college for more information. You can also look here for the roles and remits in your college.