Problems with fonts in embedded charts/spreadsheets, etc.
When embedded objects like charts, graphs, spreadsheets, etc. have fonts in sizes below 8 points, PowerPoint sometimes changes them to Times-Roman when it prints. The fonts are wrong and may also overlap or be otherwise incorrectly spaced.
The fix: choose Tools, Options and in the Options dialog, click the Print tab. Put a checkmark next to "Print inserted objects at Printer Resolution" then OK your way out of the dialog.