Rookie Roundup is a contest aimed at Amateurs licensed for three years or less. This six-hour event is held three times per year (April, August and December). Rookies can contact anybody, while "Old Timers" make contact with only Rookies. Mentoring is a big part of this event! Operating period 1800UTC through 2359 UTC.
More at: http://www.arrl.org/rookie-roundup