They're still teeny, as you see, but considering I only planted them twelve days ago, they're doing great! (The alyssums started sprouting after just four days.)
I deliberately chose seed packets that said "easy to grow" or "sturdy" or something similar, and leaned toward flowers that will smell good. My chosen plants are nasturtium, alyssum, and dwarf carnation. It's an easy project, and it gives you something to look forward to each day: have they sprouted? How big are they getting? Any flowerbuds yet?
All you need is little pots of some kind, the seeds (very cheap; check a garden center or nursery), room in a relatively sunny window (south-facing is best in winter), and potting soil. And in the case of nasturtiums, they flower best in "poor soil," so you don't even need the latter. Whatever you have in the yard should work.
Try it! Improve your mood and your indoor air quality, just that little smidgen.