This deck is ready to play right out of the box. It includes cards not just from Mirrodin Besieged but powerful cards from other sets as well. It even has a sideboard. This deck is tournament ready as soon as you open it.
Here is the deck list:
21 Mountain

1 Contested War Zone (MBS Rare), 1 Iron Myr (SOM Common), 1 Spikeshot Elder (MBS Rare), 2 Darksteel Axe (SOM Uncommon), 2 Devastating Summons (ROE Rare), 2 Galvanic Blast (SOM Common), 2 Goblin Bushwhacker (ZEN Common), 2 Goblin Guide (ZEN Rare), 2 Panic Spellbomb (SOM common), 4 Goblin Wardriver (MBS Uncommon), 4 Kuldotha Rebirth (SOM common), 4 Lightning Bolt (M11 Common), 4 Memnite (SOM Uncommon), 4 Ornithopter (M11 Uncommon), 4 Signal Pest (MBS Uncommon)

Sideboard
1 Leyline of Punishment (M11 Rare), 2 Act of Treason (M11 Common), 2 Into the Core (MBS Uncommon), 2 Unstable Footing (ZEN Uncommon), 4 Goblin Ruinblaster (ZEN Uncommon), 4 Searing Blaze (WWK Common)