When you create and run a report using Report Writer now, you will find an Export as CSV button at the top of the output page next to Save as Slide. Click it and you will get a save dialogue box. You can save the CSV file to your local drive and then open it in Excel or another application.
Especially nice, this feature carries over to a slide show. A report in a slide show will display a discrete CSV link at the bottom left of the report page.