Visualize error logs from winston (node.js)

[Update] It looks like there's Cubism which can use graphite as a source. It would be really nice if there was a project out there that uses mongo as a source.

I am using winston (node.js package) to do logging to a mongodb data store. What is a good tool to visualize mongodb data? The recommendations on mongo's website are include pentaho which is very enterprisey. I've seen Cube float around, but it doesn't seem to be what I need; I need a visualization tool so I can see counts of specific errors (stored in mongo) be updated every few minutes. Essentially what splunk does, but one that works with mongodb and is free.