Lindsay Lohan Returns from Hawaii -- Parties at Jay-Z Concert

Lindsay Lohan's Hawaiian vacation has finally come to an end ... but hours after she arrived back in L.A. last night she was already partying again ... at the Jay-Z concert.

LiLo was originally scheduled to catch an early flight so she could have appeared on "Ellen" to promote her Playboy spread ... but Lohan missed the early flight and had to bail on the show.

Lohan's rep tells us the actress offered to tape a segment for "Ellen" today -- but Ellen's people turned her down due to scheduling issues.