There are male and female characters all in their 20s. I would study all kinds of voices, accents, hoarse, lisps... you name it. If you are a male and able to provide a female voice then you're welcome to submit and vice versa. You don't have to use any specific lines but in case you're out of ideas here you go:
[CAST] Male (emotionless): "Well hello there... Say goodbye to your new friend."
[CAST] Female (sarcastic, Russian): "Funny... I'm still not interested."
[CAST] Male (main character): "This looks like a laboratory mainframe."
[CAST] Narrator: "Leave it alone! It has to be enabled first."
[CAST] Narrator: "You try hard to pull yourself together after the shock from the explosion. However, you fail!"
[CAST] Female (explaining a theory while scared, not whispering): "..something weird has happened and gave him the ability to travel through time!"
[CAST] Female (mumbling and scared): "He snapped.. Yes. That IS exactly what happened to him."
[CAST] Male (Alien technician): "You need to disconnect the cables leading to the main hydraulic controls. Then, discharge the extra pressure."
[CAST] Female (gossiping): "Oh I really think they'd make a great couple! I can't wait to see the look on Helen's face when she hears about it!"
[CAST] Male (main character): "Those mountains are huge compared to the ones I saw earlier."
[CAST] Male (main character): "Oops. Ouch. Hey! Hmmm. Yay. Aha! I don't think so. Nah. Nope. No. Okay. Nothing. It does nothing."