Do you have a great idea for an Office App?

I want to build an office app and sell it in the App Store. If you know of a product that I can build on like surfacing some functionality of SAP, peoplesoft, sales force, dynamics or anything. Maybe it’s a highly specialized calculator and doesn’t integrate data at all. I’m looking for an idea that 5 people can use right away. I’m tired of building stuff that I think is cool that nobody else wants.