An implementation backed by Node and Mongo on the server side; the only transaction data coming through at the moment are trades from the MtGox Bitcoin exchange.
By default the sample runs with a "stub" MtGox service. To switch to the live version, edit bitcoind.js. If you don't see any trades on the graph with the live version, just wait. Trades on MtGox are usually pretty frequent, but can sometimes be spaced minutes apart. As a simple test that things are working, bring up http://bitcoinmonitor.com in a second window and watch for the red dots. Hover to see the exchange name. When you see new mtgox trades coming through there, you should also see them in your bitcoin-rt window.
Below are setup instructions for OS X (with homebrew installed) and for Linux. If you're on another platform, you'll easily figure it out.
see http://www.mongodb.org/display/DOCS/Quickstart+OS+X
brew install mongodb # (~50MB)
sudo mkdir -p /data/db/
sudo chown `id -u` /data/db
mongod
brew install npm
brew install node
see http://www.mongodb.org/downloads#packages
see https://github.com/joyent/node/wiki/Installing-Node.js-via-package-manager
Assuming mongod is already running (see above):
git clone git://github.com/cbeams/bitcoin-rt.git
cd bitcoin-rt/node
npm install websocket
npm install node-static
npm install mongodb
node bitcoind.js
open http://localhost:1337