Quick answer — "Hare Hare Yukai" by Aya Hirano is the ending theme of The Melancholy of Haruhi Suzumiya.
"Hare Hare Yukai" by Aya Hirano is the ending theme of The Melancholy of Haruhi Suzumiya.
"Hare Hare Yukai" is performed by Aya Hirano.