Capable of Playing Independently?

At what age can you expect a child to be capable of playing indepently- while supervised of course?

I have a 4 yr old boy who has been...

OK, so my husband left early this morning and my 3 year old woke up as well. He decides to put the TV on and tells her to be quiet until Mommy wakes up....

[Cat Herder]

http://www.facebook.com/video/video.php?v=1545499121370

Made my morning!!!! ...