Thornton McEnery

In addition to having that 'Friyay' feeling, retail investors also spent the last day of the trading week celebrating the birthday of someone...special.

October 15th marks the 53rd birthday of Citadel founder Ken Griffin, so the self-professed 'Apes' of meme stock social media sent some of their favorite tickers flying into the green in ironic honor of their least-favorite financier.

Shares of AMC Entertainment (AMC), BlackBerry (BB.T) and other memes closed up on the day, while others struggled as the retail crowd keyed in on their old favorites to cause as much havoc as they could for the man they still blame for January's short squeeze

"Ken Griffin is turning 53 on October 15th," read one popular post on Reddit board r/AMCStock "What a great birthday present the MOASS [Mother of all short squeezes] would be."

AMC closed up 1.7% on the day, but gained 9.6% for the week as investors basked in the glow of more blockbuster releases and a shift into direct registration of shares.

GameStop (GME) --a stock backed by investors who often say they are no fan of billionaire Griffin--finished the day down 0.3% after news broke that the State of Alaska had divested 75% of its holdings in the stock, but it did pop almost 1.3% in the final 45 minutes of trading as retail investors pushed each other to "celebrate" Griffin on that ticker as well.

Other meme stocks BlackBerry and Nvidia (NVDA) joined AMC in the green, while  Bed Bath & Beyond (BBBY), Express (EXPR) and Nokia (NOKIA.HE) and fell on the day, despite a solid showing from the Dow Jones Industrial Average .

-Thornton McEnery