Walking
Going walking can be a great way to get some exercise, as it is free, and a lot of the time it can take you past some fantastic locations if you get your route right. That depends on where you live, but there is no reason not to go walking if you are out for the day, or are on holiday, as it can be a good way to see the sights without paying more money than you need to.
If you were to go on holiday to the Lake District for example, walking is the best way to fully experience all the sights and wonders that the area has to offer, as many of the attractions revolve around mountains and lakes. These are fine to see in the car, but there is nothing quite like taking a stroll down a country lane, or upping it a gear and going for a hike up a picturesque hillside.
In addition, if you are on foot then a lot of the more hidden-away spots are more available to you than if you pass them in a car, making your holiday experience that much better. You could discover a small cave you never knew existed, or find an old path that leads down to a stunning waterfall. If you are not walking, then you will never know that these places ever existed, and you would be missing out on a potentially great experience that could make your holiday even better.