rattleback rattle + back tap + spine Spinal Tap

 

 

Rattleback (a.k.a. wobblestone, celt)

 

http://en.wikipedia.org/wiki/Rattleback

 

http://demo.physics.uiuc.edu/LectDemo/descript/1148/rattleback.wmv

(online demo)

 

(Rattlebacks are widely available through online science stores such as Edmund Scientific.)

 

 


Spinal Tap (Critically lauded mockumentary film of 1984 directly by Rob Reiner whose full title is This is Spinal Tap. But the film is familiarly known as just Spinal Tap.)

 

http://en.wikipedia.org/wiki/This_Is_Spinal_Tap

 

http://www.rottentomatoes.com/m/this_is_spinal_tap/

(reviews)