Adopt a kitten from your local shelter. If you want to adopt an adult cat, ask the shelter what they need for their existing cats and how many kittens would be too many (in addition to asking them if any of their adult kitties are pregnant or in heat). Bringing in a litter of kittens will help make everyone happy!
Do not take home older cats that may have health problems. The shelters do not know when these cats can no longer live with people and often end up euthanized because they cannot find homes fast enough.