Discovered a funny one-liner to turn your tablet into an echoplex.

as root:
apt-get install gstreamer-tools

as user:
gst-launch-0.10 dsppcmsrc ! dsppcmsink

control-c to abort

Setting the volume to above ~70% will result in feedback gain > 1.0, so keep it below that unless you are jimi hendrix.

This could be a cute prank too