Catholic colleges typically celebrate religious holidays with special masses, services, and a variety of other events. There are a couple of important liturgical holidays that have emphasized festivities, and some that are just one day or service.
The Christmas and Easter celebrations are particularly special. The Christmas/Advent season is typically accompanied by special masses, prayer services, and advent wreath lighting ceremonies. There is also typically a Christmas day mass (though most students are on Christmas break), perhaps with a nativity play or concert beforehand. Campuses often decorate for Christmas as well with Christmas trees, lights, and nativity scenes.
Easter celebrations are also a big deal. Lent observances like retreats, Ash Wednesday services, Stations of the Cross, and opportunities for confession are common at the start of the Easter season. Holy Weeks brings another round of celebrations, services, and special events with Palm Sunday, Holy Thursday, Good Friday, and Holy Saturday. Many colleges will offer a special Easter Mass on Easter Sunday, often followed by a festive meal or gathering.
There are a couple other holidays that are typically celebrated by Catholic colleges. The Feast of the Immaculate Conception is usually marked by special masses and sometimes campus-wide lectures or events. All Saint's and All Soul's Days are also commonly celebrated with masses specific to the holidays, but also with special prayers for those who have passed on. Some colleges may also hold memorial services. Holidays that celebrate the patron saints of a Catholic college may also be celebrated with special masses, services, feasts, or events.
It is important to note that these are general examples, and not every college will celebrate religious holidays the same way. For more detailed information about what sort of celebrations, events, or observances, check the website or with the admissions department of the Catholic college(s) you are interested in.