My sister has curly hair and she hates the "wet" look because she thinks of it as a ghetto look so... she is now a huge fan of Catwalk brand's "Curl Shaper!" It really does work amazingly! I have completely straight hair but it is easy for me to have that scrunched/curled look so I have used it and it really does work wonderfully!
To keep hair straight... tie your hair with a small, kind-of-tight rubber band and slip it down towards the end of the tail! This will keep your hair all in one place when you sleep and under your head evenly for an even and straight look in the morning!