Cyathus striatus

Scientific name:  Cyathus striatus (Huds.) Hoffm.
Derivation of name: Striat- means "finely furrowed" or
"lined" (striate) in reference to the grooved inner surface. 
Synonyms:  
Common name(s):  Splash cups; Fluted bird's nest.
Phylum:   Basidiomycota
Order:   Agaricales
Family:   Nidulariaceae
Occurrence on wood substrate: Saprobic; clustered on
wood chips, bark, fallen branches; summer through fall.   
Dimensions: Vase-shaped cups are up to 2 cm tall and
1cm wide.    
Sterile nest surfaces: Exterior surface dark or grayish-
brown and covered with shaggy or wooly hairs; interior
surface distinctly grooved; shiny; pale gray or grayish-brown;
young vases are covered by a whitish membrane.
Fertile tissue: Gray peridioles ("eggs") occupy the bottom
of the vase-shaped cups; each egg is attached by a thread-like
cord (funiculus) to the inner cup wall.
Edibility: Not edible.
Comments: When an egg is ejected, the trailing cord (funiculus)
helps it adhere to an object it encounters.
  
More information at MushroomExpert.com:   
More information at TomVolkFungi.net:

Figure 1. Typical view of splash cups on decaying wood
substrate. Photo © Larry Grand

Figure 2. Splash cups clustered on rotting wood.

Figure 3. Eggs (peridioles) visible within the splash cups.
Photo © William Roody.

Figure 4. Forces resulting from a drop of water striking
the inside of the "splash" cup eject the eggs from the cup.
Photo © Pam Kaminski.

Figure 5. The hairy outside, grooved inside, and gray
peridioles make this a distinctive fungus.

Figure 6. The nests on the right still have membranes or
remnants of membranes around the rim of the nest.