NFL teams have done it. MLB teams have done it. The United States Men's Basektball Team has done it.  Mark Zuckerberg and Bill Gates have done it.  By Saturday afternoon, the Ice Bucket Challenge in support for ALS (better known as Lou Gehrig's disease) had reached a cultural tipping point.  Yes, Oprah had joined the fray.

But, not only Oprah, "Iron Man" himself Robert Downey, Jr. (a relative newcomer to social media) and a certain "Guardian of the Galaxy" named Chris Pratt.

You can watch Pratt's attempt to ditch the bucket by drinking other versions of "ice" here:

 

 

 

You can check out Robert Downey Jr.'s dousing here:

 

 

It's worth noting Downey, Jr. challenged Vincent D'Onofrio and his son Elias as well as "his old pal" Thor, Chris Hemsworth. Pratt challenged his co-star from "Everwood" Gregory Smith, his co-star from "Parks and Recreation" Nick Offerman (one we'd definitely like to see) and his "Guardians" cohort Dave Bautista.

To donate to the ALS Association click on the donate button in the right corner of this page.

Here are some other stars who took the challenge over the past 24 hours.

Oprah Winfrey

 

Tyler Perry

 

Tim McGraw

 

Taylor Swift and Jamie King

 

Eddie Veder Carrie Underwood