Babysitting!!!! You can take care of the children when their parents are away. Before I've got my first part time job, I babysat kids in my neighbhourhood. You could take the kids to the park, show them a movie, and play games with them. Sitting for a Saturday afternoon could earn me $20.... that was 8 years ago, and I was 15, so it was ok.
Yeah... if you are 16, get a SIN and apply for a job at MacDonald's!
There is a pet store chain called P J's Pet Store - check your phone book.
They sell all kinds of small animals for pets. You can apply a summer job there. Last time I saw many young student-look-like staff in some of the stores.
Another suggestion, try to apply a volunteer job at a zoo or pet hospital. Although you don't get paid, you gain your experience this way. Next time when you apply for a paid job, it shows some experience on your resume. It'll also look good on your cv when you apply for post secondary education.