[TOMT] Short story where kids get eaten by lions in their play room

I read this short story when I was in middle school, and it was about two kids who had this futuristic play room that had screens on all of the walls. Anything they wanted to play, they just had to say it (or something like that) and a background would appear to augment their play time.

Problem is: they were brats, and at the end of the story, their "safari" background came out of the screens and they were eaten by lions (iirc).

Anyone have any idea about the name of this story? I've googled this periodically for years, and I've got nothin'.

Thanks!

Edit: Ahhh - You guys are awesome, and I'm crazy impressed that you managed to take that jumble of word vomit and turned it into something for real. <3 PS: I don't know what to do now to show that this has been solved. Help?