Windows only: Freeware application DVRMSToolbox analyses Media Center-recorded files and marks the start and end point of commercials so you can quickly skip over commercials and go straight to the content. Similar to previously mentioned Lifextender in its commercial skipping capabilities, DVRMSToolbox keeps your files in tact and marks the commercials instead of deleting them entirely (like Lifextender does) so there's less chance of an inadvertant cut. In addition, DVRMSToolbox can convert DVR-MS files (the default recording type of Media Center) to MPEG or WMV files for portability to other devices and other useful features. For a simple guide to getting started with DVRMSToolbox's commercial detection, check out CyberNet's introduction. This Media Center favourite is freeware, Windows only.