http://pbskids.org/caillou/immersivegames/

http://www.caillou.com/immersivegames/

1. PBS Removed The Website.
2. 404 Not Found On 2nd Website.

You can find all the original Caillou Games right here:

https:/​/​www.​numuki.​com/​games/​caillou/​

I know this is a necropost and people are gonna get mad at me and no one cares, but I found a better url for playing the old Caillou games.
Instead of going to https:/​/​www.​numuki.​com/​games/​caillou/​, which only has some of the old games, you can instead go to http://r53-vip-soup.pbskids.org/caillou/immersivegames/

However, since a login shows up on the page, you will need to download an extension called Requestly and implement these rules: https://drive.google.com/file/d/1GCYDNhxrR1ubhqxpxrHCpUSsDwbGOkC8/view?usp=sharing

Alternatively, you can download a program called "BlueMaxima's Flashpoint" where people have been preserving Flash games and other webgame types since early 2018 and have archived over 60,000 games.
Most of the old PBS Kids games are in the database, so you can go there instead.

Download link for Flashpoint: https://bluemaxima.org/flashpoint/downloads/