I also work for a non-profit arts group using QBO.  Our most frequent activity that I need to track is classes or workshops.  We have been using the Class field on both expenses and income to see all the items associated with a particular workshop.  But with the new data limits coming (limit of 40 classes), this isn't going to work any longer.  Projects seem like the logical tool, but I don't see how I can create a project for the workshop, and then associate both expenses and income from multiple customers (persons paying for the workshop) for that one project.

(We're hitting this limit because we recently migrated from desktop to online QB.)