Midsummer Solstice-June 21: There is some history in this article, however, most of the article describes a Midsummer Ritual. I don't have a citation for it.
Summer Solstice-Usually June 21st: This un-cited article also is primarily centered on ideas for ritual. However, the first paragraph brings in what's happening to some of the gods and goddesses at this time of year.
Aphrodite (Summer Solstice): This article explores the energy and themes surrounding the goddess Aphrodite. It includes a ritual that "celebrates "the free wild spirit of Aphrodite, or woman's ability to bask in Her fires, yet keep her virginity and selfhood."
"The Sun is...": The sun is the nearest star and if it were hollow, over a million earths would fit inside...
Summer Solstice, Midsummer- by Crystalinks: This is a good article for how the Celtic people historically celebrated Summer Solstice.