Tad is an interesting tool for viewing any analysing CSV files and tabular data. Open a CSV file and it's displayed in a simple table. Clicking column headers quickly sorts the data by that field, and you can drag and drop headers to reorder them. That's useful, but it's also very familiar.
We thought the gear icon to the left would be a regular Settings dialog, but actually it provides more ways to configure the viewer. You can hide individual colums, sort by specific fields, display the totals of each field in the top row, even build a pivot table to better analyse complex data.