Your first step in hiring corporate entertainment is to sit down and create a task list. First, dream up the perfect event, then start working out the details of how you're going to reach that goal within the budget you've got. Only after all this is worked out should you start interviewing talent.
When you are looking to find someone to bring in to entertain your office or to provide laughs at the next company outing you should look into a corporate entertainment agency. These groups can provide exactly what you are looking for as they are representatives for a number of different entertainers.