For the last 6 months I've been working on an open source project to make Excel files and now it's at a point where I can start "promoting" it. I called it ClosedXML and it's hosted on Microsoft CodePlex.

The reason for the name is simple, after seeing how horrible it is to deal with Open XML files my first thought was "If this what it's like to work with Open XML I'd rather work with something that was closed!".

The component is coded in C# but can be used by any .Net language like Visual Basic (VB). It has many features geared toward handling data, for example you can set the value of a cell to an IEnumerable of any kind and ClosedXML will create a table from that object (it works with DataTables too).

For a full list of features as well as a plethora of examples please go to ClosedXML - The easy way to OpenXML.