What? Clicking "Random Page" sends you to a random page within my web site.
Why? Mostly for my own internal purposes, to allow me to note bugs in parts of my web site that I would ordinarily rarely visit.
How? index.html reads a file, list.js, containing a list of all the html and pdf files under /~drorbn/, along with their "relative weights". It then chooses randomly between showing a random page from my wiki (12%), a random page from the knot atlas (20%), a random page from Math 1300Y/427S - Topology (1%), a random page from my Blackboard Shots (1.5%), or a properly-weighted random page from within list.js (65.5%). In itself, list.js is made using the following makefile and the perl script filter.pl, which are run in a directory that contains a symbolic link named "web" to /~drorbn/. That directory also contains a (short) list of exclusions in a file "Excludes" which is not made available here.