Close but no Cigar:
To be very near and almost accomplish a goal, but fall short.
Cock and Bull Story:
An unbelievable tale.
Come Hell Or High Water:
Any difficult situation or obstacle.
Crack Someone Up:
To make someone laugh.
Cross Your Fingers:
To hope that something happens the way you want it to.
Cry Over Spilt Milk:
When you complain about a loss from the past.