Origin: there is a man who frequents the downtown Syracuse NY scene and who dresses like he's Richard Marx's fanclub president, from his permed hair to his leather jacket to his cowboy boots poking out of his acid-washed tapered jeans. Once when he was spotted at a bar, a waitress was asked by a patron "Hey, don't you think that guy over there looks like Richard Marx?" The waitress responded with only "He's a really nice guy" and walked away from the table. Stunned but undeterred, the patron again said to the waitress upon her return "Hey, seriously, don't you think that guy over there looks like Richard Marx?" to which she again gave only the dead-serious reply "He's a really nice guy." The patron and his friend with him were dumbfounded, and ever since, as this story has been spread, it has been becoming known as "pulling a Richard Marx" when a joke doesn't turn out the laughs it was thought it would.
Tips: when someone pulls a Richard Marx, it is best not to blurt out "You just pulled a Richard Marx!" but rather to subtly inform said offender of his failed humor attempt. Try simply saying "Good one, Richard" or softly singing "Hold on to the nights." Best yet, when you pull a Richard Marx, just call it before someone else does. Try singing "Shoulda known better" as soon as you realize you've Richard Marxed a joke attempt. This might actually redeem you from your humor failure if your company is hip to what a Richard Marx is and they laugh at you calling yourself on it!
Calling a Richard Marx can be risky if other people present are not familiar with the term. If so, you might actually end up pulling a Richard Marx also if you call it and people are confused! Think about the company present, and consider keeping it subtle, before calling a Richard Marx.
Though somewhat malicious, people have been known to deliberately cause another person to pull a Richard Marx by intentionally not laughing at their otherwise funny joke. Technically this is a Richard Marx, but it's not what the term was originally coined to have done with it.
"I Richard Marxed myself" or "He Richard Marxed himself" are never the way to express this humor failure. Simply say "I Richard Marxed" or "He Richard Marxed" if you wish to express it this way.
Person 2: I know! It's been like a Richard Marx greatest hits tour!
Person 1: Dude, didn't you get it?
Person 2: Sorry bro, my mind was on the Richard Marx concert coming to town today.