Figured I should post this because I thought this will be cool.

Link to the an event page

But to sum up most of what's on that page, these guys are going to build a giant Darth Vader (approx 4 metres tall) and a Yoda (approx 2 metres tall) and participant challenges to build lego sets the fastest.

WHAT: LEGO Star Wars Building Challenge
WHY: To celebrate Star Wars day (May the 4th) and the launch of the 2013 LEGO Star Wars collection, LEGO fans of all ages have the chance to assist in the building of a giant model of the Dark Leader Darth Vader and the Jedi Grand Master himself, Yoda.
WHEN: May 3rd, 10am to 5pm
May 4th, 10am to 4pm
WHERE: Centre Court, Westfield Penrith – 585 High St, Penrith NSW 2750
COST: Free

Not sure what day I will be there, but maybe both.