Today, Ja Rule begins his 2-year prison sentence on a 4-year-old gun charge to which he pleaded guilty to late last year. “My last day out,” he Tweeted yesterday afternoon, adding that he was spending time with his family at the movies.

During a routine traffic stop in July 2007, police say they found a loaded .40-caliber semi-automatic gun in the rapper’s $250,000-plus Maybach sports car, which they’d said they’d stopped for speeding as he left a concert in Manhattan at the Beacon Theatre. Lil Wayne was arrested separately on similar charges after headlining the same show, and later pleaded guilty, spending around eight months in jail last year.

“Laws are laws,” Ja Rule said Monday on Good Day New York, speaking on the incident, which ironically happened right after Wayne’s run-in with the cops. “There’s nothing I could really do but own up to the situation. You know, I try not to regret anything I do in life, because you go through life and you do things, and you man up to them. You own them,” he added.

Ja Rule, who had been recently preparing for the release of his new album, recently told TMZ that he plans to keep himself busy during his 2-year stay in a New York prison (most likely Rikers — the same place Wayne served his sentence) by writing a book, getting his GED and possibly learning how to play the guitar.

Fortunately, under state prison policies, the rapper/actor (who is leaving behind a wife and three children as he goes off to jail) might be able to get his sentence reduced by up to 6 months for good behavior.