We have used ELog for some time now (within the IT industry) for several things (on-call tracking, after-hours work, knowledge base and a few other uses in development).  Now that we have a good base of data, we would like to do some trending analysis.  We have used Excel in the past for this, but it is rather time consuming.  Does anyone have recommendations for tools (hopefully open source) they have used?  I know nearly anything will since ELog uses flat files, but I'm looking for recommendations that you all know works well.