Reiterating my annual request for smart people to breed. Thank you.

Great Minds Drink Alike Valentine, $5
See also this Picard digital download that says, “Lower your shields and prepare to be boarded.” Romance!

All Your Heart Are Belong to Me, $5
I just set you up the bomb.

Boobies Calculation, $4
A much more sound approach than kicking her because you like her.

Player 2 Valentine, $4
This fancy one is great too.

Carl Sagan Valentine, $5
Cyrano got nothing on Sagan.

Space and Time Valentine, $5
You should probably let those guys go.

Dr. Who Valentine, $5
Comes see the softer side of gears.

Replenish My Hearts, $8
You are a life-giving force, son.

Texting Bubble Stationery Set, $16
Maybe you’re old fashioned, and you want to text a love letter.

Papercut Protest Valentine, $5
All of us know Valentine’s Day is a fake holiday created by greeting card companies anyway. But if you’re going this route, maybe grab her some flowers too.

Plus some old guides that might give you good ideas:
I Love You, Nerd Valentine: Top 10 Valentines for Geeks
Nerds in Love: 10 Valentines for Geeks
Literary Valentines