I just read nice article about varnish from Smashing magazine and this post is the reminder for me to try it out.

I think varnish can be use with nginx also.
Here is what I found after a quick googling.
How To Install Wordpress, Nginx, PHP, and Varnish on Ubuntu 12.04

randomuser.me got really cool & realistic random user generator to use for testing applications.

RandomUser is an API that provides you with a randomly generated user. These users can be used as placeholders in web mockups, and will save you time from creating your own placeholder information.