Resolver One is an IronPython based spreadsheet. I'm still getting my head around whether there's a big enough market for an Excel replacement to support a company, but in any case it's very cool.
They have just released Resolver One 1.4 based on IronPython and includes Numpy support.
They are also trumpeting R integration. This is done using R(D)COM accessed from IronPython. Now if we just had a Mono implementation of R(D)COM to get this approach working on Linux and Mac...
Rcpp 0.12.11: Loads of goodies
3 days ago