Organizing Hackathons

If you're organizing a hackathon, you may want to go through this page for tips on preparation

Basic do's and don'ts

Don't rely on stable WiFi. Bring a router, and get to know the Internet infrastructure beforehand from the venue
Do check the intended status of essential services like Bugzilla or mxr beforehand. You don't want them to go down during the event.
If venue connection speed is problematic, present good alternatives to tools like MXR/DXR such as "ack", "grep", and "find".

Bring as many flash drives as possible with a mozilla-central clone (or whichever repo you intend to work with). Make sure each one work beforehand; some filesystems will silently discard important details like executable permissions while copying, causing mysterious build failures later.
Don't assume that everyone has Linux. Prepare for Windows users by having a local copy of all the dependencies, such as mozilla-build, Windows SDKs, etc. Note that some of the required installers are network-based; installing Visual Studio 2010 Express over a shared wifi connection is probably not a viable option.
Try to identify some easy, open bugs beforehand. Have plans for how to solve them, files to look at, etc., so you can quickly and effectively coach attendees.
The first build is long. You might want to plan things accordingly, maybe having users set up a build before the bug-hunting starts.
Consider having attendees choose tasks/start investigating solutions while waiting for build environment setup. You can still use tools like MXR/DXR while the code is being copied, for example.
Consider pairing up attendees if one person's build environment will take significantly longer to set up than the other.
When possible, consider providing access to machines that are already configured and pre-built. This can alleviate the problems with Windows-using attendees.