The following links take you to free pentagon patterns for crocheting. These five-sided designs are fascinating crochet projects.
This pentagon granny tutorial is by Sandra Petit, posted at Crochet Cabana. Sandra's pentagon is crocheted in Christmas colors, but you could make it in any color(s) you like.
This lacy pentagon-shaped dishcloth was designed by Drew Emborsky, AKA the Crochet Dude. You'll find the free dishcloth pattern at his blog.