This is what my girlfriend says:

The fastest way to a Geek's bedroom is through the brain.

Ask him for a reading recommendation -- Geeks love to be consulted about intellectual matters.

If you've got specialized knowledge of a particular subject, be sure to bring it up. Geeks tend to be attracted to experts -- the more obscure your subject, the better.

If a Geek mentions their latest hobby, be sure to ask for a crash course. Nothing will get a Geek in the mood like showing off their know-how.