A Whole Buncha Beavis and Butthead Videos
The link is a playlist on youtube of about 30 videos, varying lengths(some 15-20 minutes) of nothing but B&B riffing.
Enjoy.
https://www.youtube.com/watch?v=4iYX3cRthZI&list=PLZz8_Kp9g5Z2jeq2eEAzeBc-xIhm_PLpu&index=1