(1) When someone drinks heavily during a holiday, particularly when all of their extended family is present.

(2) An exotic mixture of illegal stimulants chosen for energy-fueling and appetite suppression.
(1) George: "Mom's in the other room sleeping even though the party isn't over, she's been on a Lohan Holiday for the entire week of Thanksgiving.

(2) Cindy: "OMG Vicky, you look so skinny, did you totes do a Lohan Holiday or some shit?"
by Luc Samatas September 13, 2009