Talking to a girl

There's a girl at work that I want to talk to. She works in a different department though, so I can't just walk up to her and start talking. I need the excuse of a situation involving her to start a conversation. But the excuse won't happen! I can't figure out when she goes on break or anything. I'll show no signs of avoidance or lack of confidence once I start talking to her. My problem is I can't have her know I'm looking for a way to talk to her, hence the excuse I need. Does anyone know what I mean? What do in this situation?

http://www.wikihow.com/Talk-to-a-Girl-Y ... First-Time

I don't know anything about your workplace, so it's hard to say:

1. Do you guys share a kitchen? Maybe you can bump while grabbing coffee
2. Where does she hang at lunch? Does she go to the smoking area? Try and befriend her friends first and ease into her 'group', or else you come on as too strong and possibly stalker-ish.
3. You can go to social work gatherings that she does, like christmas parties.
4. E-mail her.

Tell her your pet tarantula escaped when you brought him to work and you have to search under everyone's desk. Ask if she has seen him. He answers to the name Nigel.