ARRL School Roundup

There are two School Club Roundups during each school year in October and February. Each 5-day event runs Monday through Friday from 1300 UTC Monday through 2359 UTC Friday. A station may operate no more than 6 hours in a 24-hour period, and a maximum of 24 hours of the 107 hour event.

Source: https://www.arrl.org/school-club-roundup