  We introduce the Online Preference Reporting and Aggregation (OPRA) system,
an open-source online system that aims at providing support for group
decision-making. We illustrate OPRA's distinctive features: UI for reporting
rankings with ties, comprehensive analytics of preferences, and group
decision-making in combinatorial domains. We also discuss our work in an
automatic mentor matching system. We hope that the open-source nature of OPRA
will foster the development of computerized group decision support systems.
