Rock Out With Your Cock Out

[Seil]

What are some things out there that people rock out on that are normally not rocked upon?

Theramins? (http://www.youtube.com/watch?v=mW0B1sipLBI&feature=related)
Ocarinas? (http://www.youtube.com/user/docjazz4#p/c/42122E1B97804728/45/tEyfC2fLV3c)
Harps? (http://www.youtube.com/watch?v=d_vbdxwI5Ck)

To a lesser extent,

Violins? (http://www.youtube.com/watch?v=JVDRX3Ou3GI)
Harmonicas? (http://www.youtube.com/watch?v=RO9Cqkbqzmg)
Slide Whistles? (http://www.youtube.com/watch?v=WgGTdZT1dgA&feature=related)
Handbells? (http://www.youtube.com/watch?v=_c24Umv5zCs)

In the WTF category....

Vegetables? (http://www.youtube.com/watch?v=4LIMz2mL26M)

Obviously, "rocking out" is interpreted differently in each musical genre, but what instrument have you underestimated today?

[Melfice]

Would bagpipes (http://www.youtube.com/watch?v=H1iR2Wi3u5o&feature=related) count?

[Seil]

Yes.