(Well, the year is only a week old.) From the generally rather adorable Teen Titans Year One:
The Flips previously appeared in Teen Titans back in 1965.
With a classy act like that, how could they ever have been forgotten?
Teen Titans Year One issue 1, “In the Beginning …” part 1, written by Amy Wolfram, art by Karl Kerschl, Serge Lapointe and Steph Peru, letters by Nick J Napolitano, edited by Eddie Berganza, DC Comics, March 2008
“The Return of the Teen Titans”, story by Bob Haney, art by Nick Cardy, originally published in Showcase issue 59, DC/National Comics, November-December 1965, reprinted in Showcase Presents Teen Titans volume 1, DC Comics, 2006