Chasubles are Eucharist garments. In some traditions, like the Roman Catholic and Episcopal churches, the priest who will preside over communion wears a chasuble the whole service. In the Lutheran tradition, they are not required and I have frequently seen pastors put it on just before the Great Thanksgiving.
I like this option as it helps to emphasize that what happens next is an important part of worship. Whether worn every service or only for some days and seasons, the chasuble helps refocus us in preparation for communion.