Right now, there are all kinds of flowers popping up. Plenty of dandelions, but lots of other pretty flowers as well. I've already posted pictures of the Speedwell, so here's a couple other flowers that are appearing all over the lawn.
I believe this is Shepherd's Purse. These flowers are really tiny, only millimeters across.
I'm pretty sure this is a member of the genus Viola, but I'm not entirely certain of the species. I think it's Prairie Violet.