It depends on the child. A very mature and intelligent 13-year-old can be at home for several hours at a time, but an immature one or one with special needs cannot. Similarly, an immature 17-year-old...
It's a classic that everybody loves, whether they admit it or not! 1 and 2 were great but I'm not a big fan of the later ones without the original cast and umph.
Read, watch the TV, play puzzle games on your Nintendo, tidy the house for you Mum, Knit, surf the Internet, learn some more computer skills. Have Fun.
You can call a friend over and hangout. If you have a bf/gf you can call them to keep you company and have fun. Or just watch movies or clean or anything you want to do.