If you do go the card route, I'd advise a funny "Shoebox"-type card, with a note that says "All things considered, I thought you could use a laugh today. I did want to acknowledge the date, however, as no matter what happens here I will always appreciate the memories we created" (or something similar).
You could always shoot her a similar text, too.
NO GIFTS unless maybe it's something sensible, like a small Starbucks gift card or something similar.
