Well, I heard it in the Anime when Asuma was standing in front of the third's grave and was thinking of the past or somethin like that
Edit: Here you go Asuma Sarutobi
Edit II: So now, is Sarutobi a clan or somethin ??? If its the Last Name (aka Surname) then how is he related to the Third and Konohamaru ???
Edit III: OMG!!! LOL...LOOK AT THIS....
Taken from wikipedia - The Third HokageThe Third Hokage (三代目火影, Sandaime Hokage?), his surname being Sarutobi (猿飛), was the father of Asuma Sarutobi and grandfather of Konohamaru.