In the course of a good many years of teaching introductory physics, I have used a number of ploys to start an introductory physics course.
Fortunately, my classroom and the hall outside were both floored by 9 in × 9 in tiles. This gave me a built-in measuring system on the floor. I took a bowling ball and after a couple of trials rolled it, as straight as I could, down the hallway. A number of students were equipped with position-marking devices (sand in a Zip-Loc™ bag). I started to count out the seconds (my pulse rate for most of my life has been 60 beats per second, so I am pretty good at this). At every count someone dropped a sand bag to locate the position of the ball.
The students then counted tiles and helped me fill in a table of position as a function of time. Now...