At work we generally pass around a birthday card for everyone, once a year (go figure), so that on their birthday they get a card from the entire team, which is a nice gesture that involves a fair amount of work, generally on Jessica's part, with very little reward. People are of course free to get their own cards for someone, if they wish.
Yesterday was Ann Marie's birthday, which I didn't realize was coming because I somehow never got the card to sign. She had three or four at her desk, and I decided to add one of my own. I took some scratch paper from my desk—one of our brand names went from special letterhead to company standard, so they distributed the now-useless paper with the special letterhead to us as scratch paper. I took one, folded it so the letterhead was inside, scribbled it and the footer at the bottom with a sharpie, and then wrote my own card. The front said "Do you know what a birthday really is?" Inside, it answered, "It's a chance to find out how cheap your friends are. Happy birthday." I thought the irony was worth it. I even put a little fake Hallmark logo on the back. She put it with the other cards, though the fact it's paper rather than paperboard prevents it from standing upright very well.
As with all things, I hear it's the thought that counts.