So you have a house to rent — or maybe just a room. Or perhaps you’d like to pick up passengers in your car working for Uber or Lyft. Pursuing these types of business activities can be great sources of additional income. But there are drawbacks too, including those involving taxes. There are several tricky tax rules to beware, especially if you want to lease your home or part of it: A guide prepared for Airbnb landlords by accounting firm Ernst & Young runs 28 pages.