This one is all about minimal effort (and damage).
Wash and towel dry your hair then split it into a middle parting. Grab an old pair of tights and clip them on top of your head – a leg on either side. Plait each side of your hair using the tights as one of your three sections (don’t add hair to this section). Sleep with them in then in the morning, unravel the plaits carefully and break up the texture with your fingers. For a bigger, bouncier curl, switch the tights for a dressing gown tie and wrap the hair around, rather than plaiting.