What are some good investments (including small business) to get into with my partner?

My partner and I are brainstorming about ways to start a business. We thought about flipping houses. We will do our research first. What are some other things we can invest in that are really popular these days and can give us a chance to be successful? He has own a comic bookstore, but went out of business because of bad partnership. Now he'll take his chance with me. What would be good to do these days to make good money?