Make:

Modding the "Bob the Builder" talking toy - "Bob the Builder. A lot of people know him, he is an all round Mr. Fix-it handyman sort of chap. He is the subject of a TV show and videos along with much merchandising. Worshipped by a lot of children gave him confidence, possibly buoyed by these successes he ventured into fresh territory. Hostile territory. Where forces lurked beyond his fixing, forces that warped him into a twisted copy of his former self, made him into something that could change between his former chirpy self and something that looked the same but spoke in many voices most of which are not nice. Here is the tale of how this came to pass." - [via] Link.

Related:
Circuit Bending by Sabastian Boaz, Cristiana Yambo. Modify a Casio keyboard (or other electronic audio stuff) and start playing some of the strangest sounds you've ever heard. MAKE 04 - Page 88.