Ripe for circuit bending or just running through brutal effects, it's the new Beat Blenders toys: US$15 groove boxes for "ages 8 and up." Typical ad copy:

Kick those guitar lessons to the curb! Just grab
this mixer and jam! The guitar riffs will rock, bass lines will thud,
drums will rumble and walls will come tumblin' down!

That's right, kids, who needs guitar lessons when you
can run one of four alternate loops for guitar, bass, and drums? (If
anyone succeeds in bending this sucker, please let me know; happy to
host audio samples for you!) Thanks, EM411.