...or maybe even dinner, if you will build a usable table differencing tool. I have some SQLite database files under version control that I need to merge (updated on my laptop yesterday while flying, not remembering that I'd made some updates on my desktop machine as well). Ditto spreadsheets: I store all my grades in Excel now, but every once in a while, I have to merge changes made at home with changes made in the office. Both are multi-tabular data ("multi" because there can be many tables in a database, and many worksheets in a spreadsheet); after images, I'd guess tabular is the most common format that people want to put into version control that diff(1) can't deal with. I can't promise wealth or fame, but you'd sure be popular.