First and second years live on the main college site's accomodation. First years are assigned signle rooms randomly, but second years are balloted, giving them the option to choose roommates for second year shared rooms. This ballot takes place in Hilary (second) Term.
Third and fourth years live in three blocks of accommodation in north Oxford. They have the option of living in flats with anywhere between one and five bedrooms. They are balloted for these rooms in Michaelmas (first) Term.
New freshers are assigned a college family upon arrival at Trinity. Their second year parents are randomly 'married' during this ballot, held in Trinity (third) Term.
If you have any questions about any of these ballots, send an email to the JCR Secretary, who administers all three of them.