No fancy display, just a dump to console of select currencies across exchanges every time a price changes, displaying only exchanges with trades in the last two hours (currency list and how old is too old are command line options).
http://we.lovebitco.in/btcmon.py (python 2.7 source)
Quote from: btcmon.py
btceUSD price change: -0.37200000 =======
anxhkUSD : 824.99200000
bitkonanUSD : 800.00000000
bitstampUSD : 647.00000000
btceUSD : 654.63000000
crytrUSD : 600.00000000
justUSD : 750.00000000
localbtcUSD : 732.43000000
mtgoxUSD : 763.01000000
btcnCNY : 5665.00000000
mtgoxCNY : 4838.30029000
btceUSD price change: +0.37300000 =======
anxhkUSD : 824.99200000
bitkonanUSD : 800.00000000
bitstampUSD : 647.00000000
btceUSD : 655.00300000
crytrUSD : 600.00000000
justUSD : 750.00000000
localbtcUSD : 732.43000000
mtgoxUSD : 763.01000000
btcnCNY : 5665.00000000
mtgoxCNY : 4838.30029000
..
Command line options
-c, --currency, default=USD,CNY
Currencies to watch, comma separated, no spaces.
-a --age, default=7200
Hide tickers with no trades for xx seconds.
Don't restart it more than once every 15 minutes per http://bitcoincharts.com/about/markets-api/ policy.
(I'll make an exe after I make display less "dumpy")
bitcoincharts socket interface code is (from)/(as documented only in) sierrachartfeed.
Maybe this will turn into a gui charting app, but not likely. Maybe I'll make it more useful as a library, but not likely.