Lock ins are staying overnight in a building or place that is usually closed to the public. Synonyms for lock ins may include overnighters, sleepovers, after-hours stays, slumber parties, all-nighters, closed-door events, late-night gatherings, and exclusive sleep-ins. These events are often done as a fun group activity or to celebrate a special occasion such as a birthday or end-of-year party. Lock ins can be found in a variety of settings, including schools, churches, gyms, and community centers. Regardless of the location or reason for the gathering, lock ins provide a unique opportunity for bonding and creating memories with friends and peers.