Diddy's Memorial Day Plans Include Basketball, BBQ Chicken Behind Bars

Diddy's spending his first Memorial Day behind bars ... ringing in the long weekend with basketball and BBQ chicken instead of Ciroc and yacht parties this year.

TMZ has the scoop on what the rap mogul will be doing in MDC Brooklyn for the holiday on Monday -- and, it looks like there are plenty of options if he feels like engaging in some friendly competition with his fellow inmates.

Diddy and the MDC crew can play dominoes, spades and board games to determine the champion of 4 North -- the dormitory-style wing of the prison away from general population, reserved for high-profile inmates.

While Diddy's sporting some gray in his beard and hair now in court, the 55-year-old can try to flex his moves on the hardwood if he wants -- 'cause they're running 3-on-3 basketball as well!

As for the menu ... it's a ton of food you'd find at a summer weekend by the lake -- kicking off with breakfast consisting of fruit and cereal.

For lunch, inmates can grab a combination of BBQ chicken, macaroni and cheese, mixed veggies and a holiday dessert -- unclear exactly what sweet treat Diddy could be biting into.

And, to finish off the day, chicken and rice -- or tofu for the vegetarians or vegans behind bars -- pinto beans, canned corn and whole wheat bread.

All in all, it sounds like a fine weekend for someone in the midst of the biggest legal battle of his life ... with the third week of testimony in Diddy's federal sex trafficking and racketeering case set to begin Tuesday.

The trial's already featured a series of bombshell moments ... from Cassie claiming Diddy had an escort urinate in her mouth to Kid Cudi telling the jury about Diddy allegedly blowing up his car.

Diddy's longtime assistant, Capricorn Clark, is expected to testify next week.