Cut the two limes into slices. Fill a large pitcher with (ice) water and add the lime slices. You can add extra flavour to the water by juicing one more lime into it.
Add a sprig of fresh mint at the end. Place the pitcher in the refrigerator for a while to allow the flavour to infuse the water.
You can also first make ice cubes with the lime and mint. Or use sparkling water (with carbonation).