I just realized that
Bitcoin Charts charts are render on the server, so I made this simple one-liner to have an
enterprise quality background:
while true; do wget -qO - "http://www.bitcoincharts.com/charts/chart.png?width=940&m=mtgoxUSD&SubmitButton=Draw&r=5&i=&c=0&s=&e=&Prev=&Next=&t=S&b=D&a1=&m1=10&a2=&m2=25&x=0&i1=SStoch&i2=MACD&i3=AccDist&i4=&v=1&cv=0&ps=0&l=0&p=0&" | convert - -negate - | feh --bg-center -; sleep 900; done
(of course you may customize this modifying the url)
it needs the last version of
feh (for images from stdin), but you may use other visualizer if you want (eg xv -rv -rbg black -rmode 5 -root -quit -).
the only problem is the 15m time phase; polling would be rude...
screenshots: