'Grool!': The 'Mean Girls' cast reunites in a video to commemorate October 3

The cast of "Mean Girls" gets name checked every year on Oct. 3, a date that was mentioned in passing in the 2004 teen flick and has since become such a cultural moment it's celebrated annually as "Mean Girls" Day.

This year, they're putting that recognition to good use.

Over 15 years after the iconic teen flick's release, all your favorite cast members reunited in a video to spark change. "Today, of course, I'll ask you what day it is," begins Jonathan Bennett, who played Aaron Samuels and won't soon be forgotten as the guy who tells Lindsay Lohan's Cady Heron "it's Oct. 3."

Daniel Franzese (Damian) chimes in: "We're also going to ask that you give."

Using the hashtag #MeanGirlsDoGood, Lohan, Bennett, Amanda Seyfried (Karen Smith), Lizzy Caplan (Janis Ian) and more stars promoted a collaboration with the Thirst Project, which aims to build clean water projects in developing countries. They're aiming to raise $8,000.

"We all know Cady was from Africa, we want to help build a well in Uganda," Lohan said.

Also with cameo reprisals: Lacey Chabert (Gretchen Wieners), Rajiv Surendra (Kevin Gnapoor), Jan Caruana (Emma Gerber, the girl who called Regina George "flawless"), and Stefanie Drummond (Bethany Byrd, the girl who saw Cady Heron wearing army pants and flip flops, so she bought army pants and flip flops).

"There's nothing left to say, except: 'Hey guys, what day is it?' " Bennett said, letting the rest of his former castmates fill in the famous line.

"Happy Oct. 3," Lohan concluded.

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This article originally appeared on USA TODAY: 'Mean Girls' Day: Lindsay Lohan, Amanda Seyfried, more stars celebrate