Office Skill - MS Excel
Add checkbox
http://office.microsoft.com/en-us/excel-help/add-a-check-box-option-button-or-toggle-button-to-a-worksheet-HP010236677.aspx
http://www.pcworld.com/article/2042382/add-checkboxes-to-an-excel-spreadsheet.html
http://www.exceltrick.com/how_to/insert-a-checkbox-in-excel/