If your going to go for a chat up line go funny ... Something like "your not the brightest colour in the box but your my fav colour" or if you feeling bold "I have a small dick but a fast arse", there risky though.
If shes a geek, learn to solve a rubix cube and solve it in front of her, don't make it blatantly obvious your trying to impress her 'cos your not really aiming for that, solving a rubix cube is a great ice breaker, I haven't picked up a girl yet but loads of conversations are started 'cos of it and people remember me for it
If shes not a geek don't try it, just go say "hi" then wing it, most people are far to nice to say something like "get away from me", so if she doesn't want to speak you will probably get a "I'm really busy" or "I have to go".
There not so bad, either you get brushed off or score, will you risk it for a biscuit?