Andrew Mason, CEO of Groupon and one of our 100 Most Powerful Chicagoans, was fired today. But, in classic Mason fashion, he left with some flair.

"If you’re wondering why," Mason writes in his resignation letter, "you haven’t been paying attention. From controversial metrics in our S1 to our material weakness to two quarters of missing our own expectations and a stock price that’s hovering around one quarter of our listing price, the events of the last year and a half speak for themselves. As CEO, I am accountable."

The letter goes on to praise Groupon employees and hint at what Mason is doing next (it involves fat camp).

If nothing else, Mason has been a pretty entertaining CEO. Here are just a few of our favorite Mason Moments from over the years:

The time he did yoga in his underwear. Made even better by the Christmas tree in the background.

His poetry. It's been a few years, but Dandelion Bay still holds up.

His Twitter feed. Too few CEOs rant about mayonnaise on sandwiches nowadays.

His true love. Building miniature doll houses.

That time he turned down $6 billion. From Google.

Farewell, Andrew. Have fun at fat camp.