A point of sale system is a bit of software they use in shops: when they scan the barcode in, it gets interpreted by the POS system, which adds the price, item name etc. It then comes up with a total, maybe edits the stock count of the item, that kind of thing. If you wanted you could make it really quite advanced.
The translator would have one textbox, and one output field (label or similar). You could enter a plaintext query, and it would come back with the answer. eg if you enter "50kmh in metres per second" into google, it will come back with the answer. It could also work as a translator eg "computer in french". It would need a db to store the conversion data, and a fairly clever bit of code in VB to interpret what kind of query it was and do it.
Flowchart designer would be pretty good, however based on my personal experience with graphics and VB (admittedly limited) its not graet for that kind of thing. Also, similar programs are already available (visio) whereas the translator/convertor is only online, so there is an opening for an offline version.
Any other ideas?