This paper uses Excel spreadsheets to introduce event study methods to both senior undergraduate and MBA students. The Hewlett-Packard Company’s takeover of 3Com Corporation is analyzed during 2009. First, two common event study methods of the cumulative abnormal returns (CARs) is explained. Second, a lesson plan for faculty is introduced to make business students to calculate the CARs for the event of HP’s takeover of 3Com. Finally, Excel graphs of the CARs illustrate the event study findings for business students.