Horizontal (Row) Sum in Pivot Tables

Currently you can only add a sum values to the bottom of the pivot table columns. For example, we have a timesheet, where "days worked" are the column value, and "projects" are the row values. Currently we can only sum the days, which total at the bottom of pivot table on the column values. It would be extremely valuable to be able to sum along the horizontal (rows) as well. Essentially, we would see both sum values of BOTH days and projects on the same pivot table.