Wait, that gives me an idea for a mission. You could escort CJ and Madd Dogg as they drive to a concert in Las Venturas, but on the way, they get attacked by a drive-by, killing Madd Dogg and wounding CJ. You then have to chase down the attackers and exact revenge.
EDIT: Any resemblence to any actual rapper's murder is purely coincidental. If you say I was thinking of 2Pac when I was posting this, you're one stoned bastard.