I have grown night scented stock for several tears now and often wondered why its fragrance - which is fantastic - is mainly released at night and the flowers more or less closed throughout the day ?
Everyone should grow some !
Yes, a lot of people don't grow them because they don't look that good during the day but if they're grown amongst highish plants you benefit from their smell in the evening.
I agree they do smell lovely
If you like the night scent, try one of these, it's a Zaluzianskya ovata, it's a south african plant. It is superb, here in scotland I have it in my conservatory but further south it should do well in the garden. It fills the house with scent.
See the pictures in this link.