Steely Myr
After I played in the New Phyrexia Pre-Release and saw how good Tempered Steel could be, I decided it would be completely irresponsible of me to not build a deck with the copies I own. I put my Tempered Steels together with the Myr Battlespheres and Steel Overseers I've had languishing without a deck for way too long. I still haven't played it against a human, but I'm looking forward to it:
Going Infinite
As I said in my last post, this deck has an infinite mana combo that's there completely by accident. If you can get two Myr Galvanizers and a Palladium Myr on the table and you can tap the Palladium Myr for two mana, use one of the Galvanizer's to untap it, tap it again for two mana and use the second Galvanizer to untap the first and the Palladium Myr netting you two mana and setting you up to repeat the process ad infinitum.
You know what's better than infinite mana? Infinite damage! Thanks to the Myr Galvanizer, the loop not only produces and infinite amount of mana, but also an infinite number of untapped Myr which when you've got a Myr Battlesphere on the table, you can turn into infinite damage.
As I said, this combo is purely incidental. The Galvanizers are in there because they have great synergy with the Battlespheres and good synergy with Myr in general. The Palladium Myr are in there because they accelerate the Battlespheres, Sunblast Angels and Argentum Armors in addition to being something of a threat when Tempered Steel is on the table. There aren't any cards in the deck to assemble the combo and nothing to protect it if it happens into being. All that being said, if I ever happen to put it together in a game, I'm totally going to generate a million mana just to say that I did ;-)