Answer:
Some people get sponsored by doing a sport such as golf, tennis or running.
Others however who may have a habit of doing something like talking can be sponsored to have a day where they can talk. If you go onto a charity site they can give you ideas. Recently, have been going on bbc.co.uk/pudsey for ideas.
If you want to be sponsored for something else like skateboarding you would have to make a video and send it to a pro.
Hope that helps,
Soph