Cedar-Apple Rust Gall (Gymnosporangium juniperi-virginianae) - 1ST YEAR dormant stage - on a Juniper - next pic shows second year stage.

VA (8/27/10 - 9/5/10)
This example was about the size of a Walnut.

It takes two years for the life cycle of this Rust.

The first year come the dark brown, roundish, galls that grow from spores. These galls can be anywhere from 1/16 of an inch to over 2 inches across and, according to one source on the web, are somewhat kidney-shaped. The galls overwinter on a Juniper. The second year, when the Spring rains come, small pores on the surface of the gall swell and they develop elongated, orange, gelatinous projections called spore horns (as in the next picture). Next, spores are released from the horns and must find a tree in the Rose family (apples are in the Rose family). When such a tree is infected it develops yellow spots on its leaves. Those spots later in the season will produce rust-colored spores that must find a juniper to infect in order to grow another gall - and the cycle begins again.

http://entoweb.okstate.edu/ddd/diseases/cedarapplerust.htm
https://en.wikipedia.org/wiki/Gymnosporangium_juniperi-virginianae