This git repository helps you get up and running quickly w/ a EtherCalc installation on OpenShift. There is no Redis support in opensift for now, so this will fallback on using disk based json data. I am not sure this will survive a reboot.
Create an account at http://openshift.redhat.com/
Create a nodejs-0.6 application (you can call your application whatever you want)
rhc app create -a ethercalc -t nodejs-0.6
Add this upstream ethercalc repo
cd ethercalc
git remote add upstream -m master git://github.com/mscherer/ethercalc-openshift.git
git pull -s recursive -X theirs upstream master
# note that the git pull above can be used later to pull updates to Ethercalc
Then push the repo upstream
git push
That's it, you can now checkout your application at :
http://ethercalc-$yournamespace.rhcloud.com