If you drive a car that is not covered by insurance - whether it is your car or not - you have a certain amount of liability if something happens (you would have to check the laws of your state to get specifics). This might leave you trying to find out if you can get coverage on a car that belongs to someone else.
Most companies won't let someone with no insurable interest in a vehicle get insurance on it. There are, however, a few that will. I have read that esurance and pgac allow it.
If you have your own insurance company check with your agent to see if they will allow it. Sometimes you can find the information on the company's website - or you can simply call an agent, explain the situation, and ask for information on the coverage they have available.
