Start at a random person on BoxRec, I usually go to an obscure division like minimum weight, and find someone in the last position, and then click from a series of fighters they have fought or are going to fight, until I stumble upon my targeted goal. Just now I started at Gregorio Garcia (ranked 256 at Minimumweight) and traveled click by click until I go to Vitali Klitschko.
It's pretty fun to do when you're really bored and helps you get a look at who fought who. It gets a little easy though because the ultimate goal is to find someone who fought DPDL, then go to Broner, go to Malinaggi, go to Hatton, go to Mayweather, go to ODLH, go to Hopkins, go to Dawson, go to Adamek, go to Klitschko. But try playing without these names.
I don't know why I made this post but if you have moments to kill it's worth trying your luck. For those who like to waste time, here you go.