Ok, this is a fun one. Just jump in your car on a Sunday morning, find a big empty parking lot, crank the wheel just enough so that you can complete a circuit without crashing into anything, and set your cruise control to 5MPH. This will keep you in a constant gravitational field (near the surface of the Earth), a steady speed (courtesy of your cruise control), and under constant acceleration because you will be constantly changing direction (acceleration is defined as a change in speed or direction).