Theatrical expression - to move equipment and scenery into a theatre. Bump out is the opposite process. Also used in relation to the set up and knock down of stands at exhibitions and tradeshows.
Bump in is on Saturday so you are required at the theatre from 10 am to whenever.
Someone that you ignore and find as irrelevant as hitting a squirrel in the middle of the night with your car.
Hitting the animal creates a bump that easily felt but subtle enough to where you think you've just ran over a pothole or some other object but you simply ignore as you want to carry on driving home from a long day.
Jimbo: Why are you even talking to me? I don't know you, you are nothing. You are just a Bump in the Night.