I stopped watching the Challenge after their 18th seasons, Ruins, aired in late 2009 because it started to change for the worst (in my opinion) though it's still going very, very strong.
Recently, Mark Long (Road Rules S1) announced the O.G. Project: cast members who haven't appeared on the Challenge in years will come together to compete once again. I'm really excited to see this hopefully in 2021.
Anyways, I was on eBay and stumbled upon this prop from The Extreme Challenge:

This was a "check" given to team Real World after completing one of their missions. It's very sturdy and still has two pieces of velcro on the back, likely used to display the check on team Real World's wall.
I couldn't pass up buying a piece of the show's history even though it's a bit lame lol.