With only 54 hours to build an app that's the basis for a business, a bunch of people who haven't worked together before will be doing a lot of things at once. Communications challenges minimizing internal misunderstandings, include getting feedback from potential users, avoiding unnecessary chaos, planning for success by recording as much useful information as possible in case the business goes forward.
What tools (chat, wikis, discussion forums, Google Docs, LiquidPlanner, ManyMoon, Basecamp, StackExchange, etc.) -- work well in this situation?
Most of the tools you mention are really too much for a startup weekend; you have to consider that you'll be all in the same room, and for a short amount of time. What works
To collect user feedback and conduct surveys we used Wufoo and I recommend it.
You might consider a free trial of FogBugz and Kiln. You can add as many users as you need for the trial and you get a full-featured task management system combined with excellent source control. I'd recommend spending a little time getting comfortable with the tools before diving into the weekend.
Disclaimer: I work for Fog Creek Software and live within FogBugz every day.
What you mentioned is good. Also, Dropbox is a great idea as it allows you to have a "cloud folder" that synchronizes automatically to every computer of authorized participant. Good for storing a "common" folder structure containing documents, tools, etc. It's also free for a 2GB capacity which is more than enough for a small startup.
In addition, you might consider GitHub for common source control. It's free for open source projects, and has a nominal fee for proprietary software.
I’ve had a great experience using Microsoft Project 2010 for project management. It’s really simple and has features to keep you updated on current project details, allows you to start new ones, and is great with collaboration. If you want to check it out, they have a free 60-day trial running right now.
You could always use Atlassian tools if your team is less than 10 people. They practically give them to you.
AgileZen has been used by many teams during startup weekend since it helps with organizing all the work and focusing on what's important.
I don't mean to spam (I'm one of the co-founders), but I'd be happy to give you a free startup plan (5 collaborators, 5 projects). We love to support startups, and we know that most people aren't going to want to buy the tool just for a proof of concept.
Anyway, if you're interested contact us at givingATagilezen.com and mention you're participating in startup weekend.
You can try http://www.proofhub.com/. It is an online project management software that enhances management over projects and these can be managed in an organized, scheduled and more professional manner. Team members can quickly and transparently communicate and collaborate over project matters and resolve them fast by sharing their views and suggestions. Progress over projects can be precisely tracked and controlled. With the help of this tool, projects can be managed within the constraints of time, budget and resources.