Paralysis (Modern)

Use reachers to get Urza's combo and Karn, the Great Creator.
If opponent has creatures out, use Karn, the Great Creator to fetch Ensnaring bridge, use all the cards you have in hand.
Use Karn, the Great Creator to fetch Mycosynth Lattice: opponent cannot use any mana, cannot attack due to Ensaring bridge.
Use Karn, the Great Creator to fetch Door to Nothingness, pay its cost easily thanks to Mycosynth Lattice #3, win.

Ghostly Flicker can be used as a defense to blink Karn, the Great Creator when attacked (only after Mycosynth is out, otherwise Karn, the Great Creator is not an artifact). Also it's "free" if you pay for it using Urza's Tower and blink it as well. Blinking Karn, the Great Creator will also reset his Loyalty to 5, so you don't have to wait to fetch Door to Nothingness.
Fog bank is a nice and cheap defense against strong creatures
Twiddle can be used to untap a land, tap an enemy creature, untap Door To Nothingness as soon as it comes into play.

Weaknesses:
You can loose before you can get your combo out, if cards don't like you.
If Karn, the Great Creator gets killed, you're screwed. There are lots of condition to account for when using this deck to make sure that you can take out your Karn, the Great Creator safely. If you miss one, you'll loose.
Creatures with 0 attack can get through Ensnaring Bridge, and still do some damage with bonuses like Exalted. Also, 1/1 creatures mean you have to have 0 cards in hand to lock them. Use Damnation / Wrath of God to elimitate these.
Counter spells are a hard counter to this deck, but can be mitigated with Condescend.
Passive damage abilities like Eidolon of the Great Revel can be annoying, but Filigree Angel can easily bring you 30 life when Mycosynth is out.