How about raising money for the handicapped children? → Let’s raise money for the handicapped children.
It's not good for you to stay up late. → You should not stay up late.
How about organizing a craft fair? → Let’s organize a craft fair.
Why don’t we recycle cans and bottles? → You should recycle cans and bottles. (This can also be "Let's recycle cans and bottles" if the prompt was "Let's")
Let’s have a fun run on Sunday morning. → How about having a fun run on Sunday morning?
Let’s go to the movies. → How about going to the movies?
Let’s go to the cafeteria this afternoon. → What about going to the cafeteria this afternoon?
How about having a craft fair? → Let’s have a craft fair.
Let’s play chess tonight. → Why don’t we play chess tonight?
It’s a good idea to join an English course to improve all the skills. → You should join an English course to improve all the skills.