Algodoo

This is the economy version. Only $19.95 if you order before midnight. It will make polygons of any size and with any number of sides. It also allows you to choose the size based on the size of an inscribed or circumscribed circle. Made for function, not looks. If you prefer an easy to use polygon maker, then use Xray's POLYGON CREATOR (updated).

Note: To get past the number of sides limit, I used Kilinich's scene.my.xFor function.

Xray, Feel free to use anything in this scene.