I just field-tested this and it's pretty golden. However, it requires you to have some type of phone that can access e-mail -- I have an iPhone, which is a nice added DHV since girls are still fascinated by them for some reason.
At some point in your interaction (I usually do this in A2 for those who study MM) pull out your phone (it can be while she's talking if you want a subtle neg) and stare at it intently as if you're reading something. Then look up, grin at her and say, "Oh my god, this is EXCELLENT! I just got this e-mail, and I've won five million dollars!
"Delivered right she'll understand and laugh, then you continue, as if you don't know it's a scam. "This is the best thing that's ever happened to me! It says here that all I have to do is send my social security number and bank account number to this Nigerian address and they'll give me five million dollars!
"I've actually sent myself an e-mail from an alternate address that I saved in a folder so I can call upon it at all times.
I find this is a nice routine to display humor and there's a lot of different threads you can go into afterwards -- start sharing high value pictures on your phone, talk about crazy spam e-mails you've gotten, etc.
It's also an easy way to transition into getting an e-mail close -- tell her to put in her e-mail address afterward so you have someone to forward all of your chain letters to, or whatever.
Ran this again today, always gets laughs.