How To Get X11 Working On An EC2 AMI

It's actually pretty easy, but worth noting:

ssh ec2-user@ec2machine
sudo yum install xauth xeyes

ssh -X ec2-user@ec2machine

In short, the magic's in installing Xauth and then re-logging in with the ssh -X flag.

And I admit, xeyes isn't strictly necessary, but I find it's a nice, lightweight confirmation that both display and mouse are working as expected.