At mass some time ago, my parish had a special ceremony to send people to the Rite of Election. What is that and who is it for?

The ceremony you saw was one of the rites associated with the Rite of Christian Initiation of Adults (RCIA). This is a process of catechetical and spiritual preparation, following the practices of the early Church, for adults who wish to become Catholic. Various rites mark the stages of the journey, from the time when a person declares his or her desire to enter the Catholic Church to the culminating moment of the sacraments of initiation. Shortly before their initiation, candidates are sent from their local parishes (in the ceremony that you saw) to the bishop, who presides at the Rite of Election. The bishop asks the candidates to declare their faith in Christ and asks the community to affirm their readiness to receive the sacraments of initiation. Candidates inscribe their names in the Book of the Elect, which is then signed by the bishop, who calls or “elects” them for the sacraments. The bishop is a symbol who unites us to the universal Church, and thus ideally he should play a role in the initiation of every Christian within his local Church. (This is why he is the ordinary minister of the sacrament of confirmation.) However, the bishop cannot be present at the initiation of all the adults participating in the RCIA, who typically celebrate baptism, confirmation and first Eucharist at the Easter Vigil at their local parishes. Thus the Rite of Election is the opportunity for him to interact with these candidates and for them to experience the embrace of the universal Church as they prepare for initiation.