Excelsior: Bringing the Benefits of Modularisation to Excel
  Excel lacks features for modular design. Had it such features, as do most programming languages, they would save time, avoid unneeded programming, make mistakes less likely, make code-control easier, help organisations adopt a uniform house style, and open business opportunities in buying and selling spreadsheet modules. I present Excelsior, a system for bringing these benefits to Excel. 
Jocelyn Paine