Do you think I should ask a girl out that my best friend has a crush on?
Why would you want to ask her out?
I'm really bored and I need something to do.
Dating is already hard enough without adding the extra baggage of dating a friend's crush. If you value your friendship, you will consider their feelings before asking the girl out.
I'm already interested in her. I'm going to ask her out anyway. It's not like anything will happen to our friendship.
Have you told your friend that you are going to ask her out? I'd suggest telling them upfront and explaining that you are not disrespecting them. Just being honest will go a long way to maintaining the friendship.