The following set of ribbons is available with every document that is opened in Excel.  Other ribbons are available for specialized tasks and will only appear when needed.  An example is the Chart ribbon.

Home: contains formatting and editing icons

Insert: objects into the file, such as pictures, charts, header/footer, and PivotTables

Page Layout: set margins, page orientation, gridlines, and headings

Formulas: functions, formulas, and AutoSum

Data: data from other sources, such as Access, text, or web, validation, and sorting tools

Review: spell check, thesaurus, comments, and workbook/sheet protection

View: views of the spreadsheet, zoom, macros, formulas, gridlines, and switch windows icon to switch between open spreadsheets