If you need a really last minute gift, try this nerdy card game you can print on card stock and play today. Gut Check, designed by microbiome researcher David Coil, pits your microbes against opponents': you can contract infections, take probiotics and watch antibiotic resistant genes spread through the population.
It looks genuinely fun. The table in front of you represents your intestines, and you can fill it with microbes: beneficial ones, pathogens, and "opportunistic" microbes that live in the beneficial zone until you draw a card that changes your health status and gives those germs a chance to change sides.
You can clear out the pathogens with a faecal transplant card, or you might draw a tetracycline card that kills any of your microbes that aren't stacked with an antibiotic resistance card. There's even a homeopathy card that does absolutely nothing.