If you're a musician, even a mediocre one, how about a song? If you already have the instruments and equipment it's free and it will win you *massive* brownie points.
CSB: Last year I wrote, played (guitar, bass, keyboards, percussion pads), mixed, and produced a song for my girlfriend. Now in all honesty I do this sort of thing as a hobby so the mood and lyrics were the main challenges but even if you have just have an instrument, mic, recording device, and you know four chords even a horrible song will be great. You're not distributing it.
BTW we're still together. Also, this is why I also always make my own cards.