Here are "Prince and Princess" Crowns made with Lego Technic parts. The Prince Crown, made primarily with Part 32016 (#3 Technic Connectors), is oval to fit your head shape. The Princess Crown has lots of Part 41666 (Technic Arms 1 x 7 with Gear 9 Tooth Double Bevel Ends) pieces, and is quite comfortable.
About this creation
You can make your own Lego Technic Crowns custom-fitted to your own head, by adding and subtracting elements. The large, yellow Prince Crown has Technic Axles of various lengths fitted between the #3 Technic Connectors. I used 1/2 Bushes, Technic Bushes, and various Technic Connectors to slide along the axles. There are various gem "rocks" imbedded into the "X" of Technic Connectors and Technic Pins with Stop Bushes. I used Bionicle swords and "skull" Large Figure parts to deoorate this 100%-Lego crown.
To make your own Prince Crown, start with a single ring fitted to your head, then place 3-long (3L) Technic Pins in ALTERNATING holes. Build your second ring and slide it down over the 3L Technic Pins of the first ring, then pop 3L Technic Pins into the empty vertical holes of the #3 Technic Connectors. That way, successive rings will be connected together as the crown is built upwards. Keep alternating 3L Technic Pins as you build upwards.
The smaller, silver Princess Crown has a "springy" feel that conforms to the shape of your head. I used vinyl lacing to keep the Princess Crown from spreading apart, but Lego purists can use official Lego thread (used for Lego winches) instead. The double-bevel gear teeth mesh well together. One can make Technic bracelets and headbands (with or without the gems) the same way.
Large, high-resolution pictures are available at http://www.brickshelf.com/cgi-bin/gallery.cgi?f=434691 . All Hail the Prince and Princess!