The Boost module works by caching static versions of pages, and serving them to anonymous users. Because Boost caches pages in flat HTML files and the server doesn't hit your database, pages are sent to the users much faster, sometimes in as little as 200-300 milliseconds, which will seem almost instantly. From the Boost module page: "If you are on shared hosting this is your best option in terms of improving performance."

Installing a web server is very easy in Ubuntu, just enter a few lines in the terminal: There is no need to install and configure each part of a LAMP (Linux-Apache-MySQL-PHP) installation individually. You can also install other programs this way. The downside is that all components are installed automatically, and not reviewed by you. But as long as you only use the web server locally (localhost or 127.0.0.1), and don't open up for access from the Internet, it should be safe.