For the past two months we've been working on a project to refactor an Intranet application at work.
The original system used our SAP backend on an AIX/Linux cluster, a Java Based middleware system on NT Server, and a Perl/Apache front-end on Linux. Last year we moved the Java layer off the awkward to administer NT system onto the front end Linux system, and fixed some code, but found that the Java/XML middleware system was so hideously broken it was going to be easier to write a new AppServer from scratch than to fix it.
So in two weeks, I wrote from scratch, a Perl/SAP middleware framework (with a little help from CPAN), and for the last 6 weeks we have been configuring it up to replaced the whole of the earlier Java middleware system. This week it's had some testing in our QA environment, and other than a few xhtml/css glitches it's proved to be very robust, and seems to be passing the tests okay.
I think I've been working on this project on and off for about 50% of the past three years. It's amazing to think that the new bespoke Perl/Apache front end has replaced months and months of work with the commercial Java/XML/XSLT monstrosity.