The Scooby-Doo Project is a Halloween special that aired in commercial segments during Cartoon Network's Scooby-Doo, Where Are You! marathon on October 31, 1999.
Each "commercial" was a mix of live action handheld footage with traditional hand drawn animations which parodied its source material, The Blair Witch Project (1999), very well.
You can watch the 20 min youtube video (linked above) which pieces all of the segments together.