I'm a programmer in finance looking to transition to web apps. I'd like to build a few web-based tools which I would make free and open-source. I've come up with a list of things including stock screeners and retirement savings calculators.<p>Is there anything I can build that you'd find useful or that you would recommend as a good portfolio piece?
A web tool that took a CSV or JSON endpoint and ran a few R/Python/whatever scripts to see what the mean/mode/min/max of each column was, if there were any strong linear (or other types) of correlations, etc.<p>A lot of example datasets can be found on opendata.socrata.com, data.gov, data.atf.gov, data.cityofchicago.org, and more.
A mobile/web app maybe meteor stack w/ cordova if you wanted to go cross-platform. I'd build a calculator to end all calculators -- normal basic calculator, but have tabs for other types of calculators like Mortgage, Retirement Savings, etc... Basically take every type of financial calculator and bottle it up into a single app.
I'm working on a graphics/plotting DSL embedded in HTML5 web-components partly inspired by the ability to do customizable financial graphs. If you're interested in collaborating on a few financial graphs in HTML5/SVG/D3, PM me. I'm also transitioning to freelancing and creating a startup and would like to open source some more code (especially good demos).