This tiny fungus (6-8 mm in diameter), possibly Cyathus striatus, is hard to find, but the edge of the trail through the woods was covered with them today. You can see different stages of development here, from a rough little knob to fully open "nest" with "eggs." Those eggs are filled with spores that are dispersed when raindrops hit the nest and bounce the spore sacs into the air. See MushroomExpert.com for more about this fungus.