Microsoft's Karen X Cheng announced her resignation from Microsoft today in a sing along video. Cheng, who reveals in the video that she has worked on the upcoming Office 15 software, sings along to Don McLean's American Pie with her own lyrics. After working on Excel for nearly three years, Cheng is departing Microsoft's hallways for EXEC, a startup based in San Francisco.

We have reached out to Microsoft for comment on Cheng's departure, we'll update you accordingly.