I've always done a variation of 'dude who kind of looks like me', because fat bearded dudes are common in stuff.  Honestly don't have a ton of pictures of myself when I did these.   But most recently, I've done a lot of Big Lebowski references, so a lot of these won't be recognizable unless you've seen it.  I know there were others I had done, like a ninja, homer simpson, etc, but that was pre-facebook, I think.  Always look for new suggestions.

2019 - In Loving Memory of Donny, who loved bowling.   

2018 - Dude and The Jesus.   I did an entire talk as the Jesus on Role Specialization in Eve as well.

2016 - Walter from the Big Lebowski

2015 - The Dude from the Big Lebowski, with a White Russian at Lunar Brewing in Villa Park, next picture is my friend Mike doing Task Master

2014 - Ants in my Eyes Johnson from Rick and Morty

2009 - Jamie Hyneman from Mythbusters

2007? - Carl, Aquateen Hunger Force