PBS Kids PLAY! (lost children's internet service; 2000s-2015)
PBS Kids PLAY! was an interactive gaming site that you could also download that taught young kids from the ages 3 to 6 reading, math, social studies, science, and more. The site was taken down June 30, 2015 due to it having "obsolete technologies". meaning it used Adobe Flash Player. Not much is known about it, considering it has barely any evidence of its existence.
A download link can be found, but it won't connect, as it tries to connect to the link it gets its info from, but the link is dead.
A subreddit for the site can be found, discussing the service. Many videos of the service remain, but the actual site is down, and will probably not surface anytime soon.