Avidemux offers simple video editing for your PC, but packs many more features than that. This open source project is great for DVD/DivX converting and editing. Avidemux also has scripting support for automation - and even offers DVD authoring (this requires 3rd party, but still open source software e.g. dvdauthor).
Avidemux is a free video editor designed for simple cutting, filtering and encoding tasks. It supports many file types, including AVI, DVD compatible MPEG files, MP4 and ASF, using a variety of codecs. Tasks can be automated using projects, job queue and powerful scripting capabilities.