I had no problem installing the Play! framework on Windows but can't troubleshoot why it's not working on OS X.
I grabbed the latest version and unzipped it to a directory. I run the Unix executable file and get the Play terminal. At the end of the terminal it says:
[Process Completed]
I can't type in the terminal as well.
You can not run the play executable from the desktop. You must run it from an open terminal window. Go to Applications -> Utilities and start Terminal.
Furthermore you need to add play to your PATH:
mkdir ~/bin
ln -s <path to your play home>/play ~/bin
echo "export PATH=~/bin:$PATH" >> ~/.bashrc
. ~/.bashrc
Now you can run
play new appname
from the Terminal window.
UPDATE 2015: The play command has been superseded by Typesafe Activator.
If you have homebrew installed then you can do 'brew install typesafe-activator' to install Typesafe Activator. This will allow you to use 'activator' commands instead of play commands.
It's also worth noting that most commands you would use are available directly from sbt. Personally, I would only use activator to create a blank project. From then on, I do day-to-day tasks from sbt. (E.g. 'sbt ~run' to run the play app in dev mode, with the ~ so it is reloaded every time a file changes.)
Old answer from 2012:
The easiest way is to use MacPorts or Brew. If you have brew installed, you can just run:
brew install play
Creating a bin folder, containing a symlink, which is on your path is also a good idea - as Andre suggested. It involves a few steps, but you will likely want to easily add more applications to your path in future.
If you are used to Linux and its package managers checkout http://www.macports.org/ You could then simply install play (or loads of other stuff) from the terminal
