Rihanna -- LOOK AT ME ... Look at Chris Brown

8:47 A.M. PDT -- We're told the game was a Roc Nation charity event. Rihanna was scheduled to be there and Chris was supposedly a "surprise appearance."

Rihanna is ridiculous ... and thirsty like Moses wandering the desert.

She showed up in the front row at a charity basketball game Thursday ... eyes trained on ex-BF Chris Brown.

Now that she's with Drake again and not Chris Brown again ... you'd think she wouldn't fuel the fire. But then again, who are we kidding?

It's a special kind of insult to Karrueche ... who's back with Chris after being repeatedly humiliated by whatever continues to transpire between him and Rihanna.

Your move Karrueche.