The Song:This famous horn riff comes from a song performed by Marva Whitney. It has been sampled by many rap artists, most famously by DJ Kool in a bad-ass early hiphop classic "Let Me Clear My Throat."
David Brown, one of the Brass Menagerie (Beck's horn section on the Vultures tour), used to step out and play this riff near the end of live versions of "Nicotine & Gravy." The best example of this was on The Tonight Show in 2001, where David Brown got his showcase on national TV.