A combination of the french word "Vendredi" meaning "Friday" and "Laundry". The Friday you start your laundry, sometimes being finished over the course of the weekend.
Most busy people only have this time available to do laundry, due to a hectic weekday schedule, and usually things to do on the weekends as well.
Mark: Hey want to go clubbing tonight?
Jack: I can't man, it's Laundredi.
"Crap! I have a tournament this Friday. Laundredi will have to be pushed to next week."
Jen: Gee, Alice, you've got a huge laundry pile!
Alice: Yeah, with work and midterms I've been busy. I'll probably do it Laundredi.