You can knock up this delicate lemon sorbet from scratch in minutes, then just freeze and enjoy.
Place the sugar and water in a pan, bring to the boil and simmer for 5 minutes. Remove from the heat and allow to cool for a while. Zest and squeeze your limes and lemons and chop your peppermint. Mix everything together in a plastic or earthenware container and place in the freezer.
Generally a sorbet takes 2 hours to set. Try to stir it around every 30 minutes if you remember.