A web app a week sounds like a pretty brisk pace to me -- but then again my knowledge of web development is rather outdated. What technologies would you use to build a web app in 7 days in 2013?
Perhaps not if you consider they don't need to be polished or great, or (depending on what you're making) perhaps even finished. You just need to work on it enough to get an idea of 1) how enthusiastic you really are about it and perhaps 2) what the market or audience looks like (but mainly 1, because that's what will motivate you or not to spend more time on it).
The might not even be the most time consuming activity, especially if you consider what one can make in a single day (see for instance https://news.ycombinator.com/item?id=6097155)
