Elm Oyster - Hypsizygus ulmarius
Pictured here as you are likely to encounter it, high up in a tree. The species name "ulmarius" refers to the fact that Elm trees re one of its hosts. I think I've only found it on Box Elder trees.
Orange Mock Oyster - Phyllotopsis nidulans
Carbon Balls - Daldinia concentrica
Stinkhorn - Phallus sp.
This is the "egg" stage of the stinkhorn before it fully develops and assumes the shape that the genus is named for.