Tough question... My most cherished pastime is gaming, and that hobby is the source of most of my friends. If I couldn't play/run any more for some reason, I'd be bereft.

On the other hand, I'd probably catch up on my reading. During my lengthy period of under/unemployment, I made a lot of use of my local library. Even if I lost my car, it's on the bus route, and the books can be checked out free. If they don't have the book you want, they can borrow it from another library for you. If I ever have enough money to make a substantial donation, it'll be to the library.