jon wise wrote:If I run Scratch on the laptop, how do I set up scratch to broadcast to a url other than localhost?
No need to set any IP etc for broadcasting since it.. broadcasts. What you *do* need is the IP number of the Pi running the Scratch so the clients can be connected and know what to listen for. Now, there is currently a bug that makes that more annoying than it should be; a while back something was changed in the Debian world (from which Rasbpian is built) whereby the old api for finding out the IP number was deliberately messed up. Since I didn't know about this until too late, the current Scratch will tell you the IP is 127.0.1.1, which is not very helpful. It's fixed for the upcoming release, by the way.
So, you'd need to manually use something like ifconfig to find your Pi's IP. You'll get a longish listing of gibberish but you need to look out for either 'eth0' or 'walnut' and there should be 'init addr: 192.168.1.42' or similar.