The RawLoadTester application is a free Open Source tool to load test websites. It does not have many features but it is useful in situations where using a more comprehensive load testing solution (e.g., Apache Flood) is not practical.
The application calls the URL you select as many times as you choose and tells you how long it took the server to respond. It writes some additional runtime details to the PHP log file so you can optionally do more granular analysis afterwards. Although the server processes most of the statistics, all URL requests come from the browser. You can run as many browsers and workstations simultaneously as you want.
It is possible that non-programers can install and use this application (e.g., junior testers); but, these instructions and the program itself assume the installer and user are familiar with their webserver configuration.