My project ideas are not as clearly-defined as some of yours, so here is a list of possibilities:

1. Similar to @laurakane, I’ve been thinking about a researching software that will help people study for comprehensive exams like the Orals. This software would be very similar to Scrivener, and do most of what it does already, but with a larger emphasis on a few things (see below). It would also be neat if, unlike Scrivener’s linear organisational structure, this program could be more laterally-structured– notes flowing outwards on a Prezi-like model, and a CommentPress-like function that would allow floating notes. Also, it would have:
– keywords. Scrivener already does this, but I’d like to increase the emphasis on keywords and recurring ideas (esp. re: grouping and sort/find functions), maybe by an automatic recognition software?
– sorting. Related to the emphasis on keywords, this program would be able to pull key quotes out of the notes and research based on recurring keywords, so that you can see all the quotes that relate to, say, “ruins” on one handy-dandy screen and print easily.
– integration with a scanner. Because the really annoying part about studying is the aspect of writing down quotes, it would be neat if this thing came with a pen scanner included for those of us who still like or need to read on paper.

Of course, actually creating/writing such a thing is completely beyond my wildest dreams.

2. The Conference Social
This is a much simpler idea — we’d have a map, and on that map, we’d pin down all the places that academic conferences are happening. I assume it wouldn’t be hard to get this information automatically from discipline-specific CFP lists, and to allow users to sort by discipline to see where and when in the world their conferences are happening. Additionally, each location would link to related cultural and other events (maybe organisers themselves would like to add certain things, as lots of conferences have tie-ins with local theatres, museums etc., for their attendees). Lastly, although I am acutely against things like FourSquare, I suppose it would be nice for those who are interested, to be able to “check in” at conferences for networking purposes.

3. Walking Tours
Who doesn’t like New York? Not tourists! This idea for a website would take tourists out of the Times Sq.-nonsense-gridlock and take them to further-away sections of the city (maybe even, gasp, into the Bronx!). We would provide detailed pdf downloadable maps, for a small fee, which would give you historic and cultural information about neighbourhoods and especially, the best way to get around without getting lost on the subway. The strength of this project would be in its information (people who live in the area giving insight, relatable commentary, up-to-date event listings, customisable information for groups, current photos of the route to make sure ppl don’t get lost) and the relatively low cost. I envision this as something that comes with a mobile app component.