.net – How to get Excel-like formulas in .Net

• Should I use a commercial component?
• Should I roll my own expression
  evaluator?
• Should I roll my own
  dynamic language?

I know programmers are notorious for wanting to write their own language, but this is not the case here. The less work, the better. Lets assume that compatibility with Excel formulas is not a strict requirement; if there's a snappable component that uses formulas that aren't exactly the same as Excel formulas, that's fine.