I've been working on a node.js project for the past few weeks and finally put it into production. The site/webapp seemed to be running quite happily until I checked the memory stats on newrelic, there seemed to be a memory leak within node.js.
It was only small but over 6hours had eaten up around 200mb on the server.
After some debugging (using node-inspector) I found it was one of the modules, fortunately it was relatively easy to switch to something else (something without memory leaks).
Now running using around 16mb.