My former boss has retired and to be occupied, he engaged in a build and sell business. He would usually buy an old house for refurbishment but sometimes he also buys a lot and build a new house. It is hard work but he was able to compose a complete team - architect, engineer, construction workers like plumber, carpenter, electrician, etc. Although the business is quite stressful, he earns 50% of his capital investment. Not bad, eh?