In the American folk tradition, guitar tunings are often named after the most iconic compositions composed within them. For example, in the mid-19th century an Ohian by the name of Henry Worrall wrote two pieces for parlor guitar, “The Siege of Sebastopol” and “Spanish Fandango”. The former was arranged for open D tuning (D,A,D,F#,A,D) and the latter for open G tuning (D,G,D,G,B,D). Colloquially, these tunings came to be known as “Vastapol” and “Spanish”. If you'd like to learn more about how parlor music and the Crimean war influenced the roots of the blues, check out this Salon article: http://www.salon.com/2014/03/23/talkin%E2%80%99_siege_of_sebastopol_blues_how_the_first_crimean_war_helped_create_rock_n_roll/.
I propose that Open C tuning (C,G,C,G,C,E) henceforth be known as “Sun Tuning” in honor of the late, great John Fahey's “Sunflower River Blues”. I love this tuning. From “standard”, the lowest string goes two whole steps lower, and the highest string stays right where it is. It's a wide, enveloping tuning that will make you feel like you're basking on the banks of the Sunflower River, itself (the tune was named the Sunflower River which ran along the Dockery plantation in Mississippi, where the delta blues was born: https://en.wikipedia.org/wiki/Dockery_Plantation).
Read Fahey's thoughts on Open C here: http://www.johnfahey.com/CTuning.htm