Circle of death
A strange, archaic term for "three-way tie."
Occasionally you can get a five-way tie, where everyone is 2-2 among the tied teams. The latter has happened during a Penn Bowl and a David Scott Hamilton Invitational Tournament (Maryland juniorbird).
A variety of tie-breaker methods have been proposed. It is considered good quizbowl to avoid paper tiebreakers like head-to-head, PPG, or bonus conversion when possible, though they are used when time or the number of questions is limited. The current ACF rules provide for the use of PPG and then bonus conversion if there are not enough packets to play off the tie.