Students' procedural knowledge and conceptual understanding of matrices can improve when they use technology, in particular spreadsheets, as a tool. Complex real-world applications of matrix calculations are time-consuming and prone to errors if done by hand, yet calculations can be performed easily with spreadsheets. In this article, the author describes a Spy versus Spy team activity for a precalculus class that required students to use matrices to encode and decode messages. Overall, the students enjoyed this activity and asked for more like it. Students of all abilities were able to meaningfully participate and work together, even with distance learning. It was educational, fun, practical, and helped build students' identities as "doers of mathematics."