What: The Woodstock-era melody-makers Crosby, Stills & Nash bring back peace and love in this benefit concert. Why: These Rock and Roll Hall of Famers are the voices behind the classics "Marrakesh Express," "Helplessly Hoping," and "Teach Your Children." Bonus: Proceeds from the tax-deductable tickets go to the American Transplant Foundation. Details: Thu 8 p.m. Wells Fargo Theatre, 700 14th St. $250-$1000. For more information, call 303-757-0959 or visit www.americantransplantfoundation.org.