Not only did Laura Prepon do a voice in Halo 2 but Bungie also mapped her face as well. The same goes for Michelle Rodriguez (The Fast and the Furious). Upon chasing the Scarab over the enormous suspension bridge you'll come to the tunnel. When you get a bit inside there'll eventually be a roadblock. In the Warthog that peels up is a redheaded female Marine, voiced by and mapped after non-other than Donna Pinciotti from That 70s Show. Check IMDB for her bio - her voicing credits are listed there - you won't doubt it upon hearing her speak.