N item drop cap

The 'Exceedingly Rare Special Items' are the different knife models. Knives unboxed can come in either a normal version or also have the chance of coming with StatTrak.

From Steam News:

Weapon Cases have a chance to contain new knives and StatTrak weapons, which track all player kills with that weapon.

The different knives that can be unboxed are:

• Bayonet
• M9 Bayonet
• Gut Knife
• Flip Knife
• Karambit
• Huntsman Knife
• Butterfly Knife
• Falchion Knife

The ★ symbol is the CS:GO version of Unusual. Knives unboxed will have the following name:

★ KNIFE_TYPE | PATTERN

So if you unboxed a Flip Knife Night, you would see:

★ FLIP KNIFE | NIGHT

I answered a similar question to this: How Do I Get More Guns?. Noticed that your question was posted a few hours before that though.

This is the new "Arms Deal" update which went live on 14/08/2013. Valve released a really good FAQ on it, which can be found here.

The bits of interest for your particular question, "How do I get item drops?":

• Timed weapon drops, just by playing on official and community servers (VAC enabled) in any game mode.
• Opening dropped weapon cases with a weapon case key.
• Trade weapons with other players through Steam's Trading interface.
• Purchase them from other players through the Steam Marketplace.

Regarding the first point, these are obtained for play time over the course of a week. As your play time increases, the drop rate will slow down. This is reset when the week rolls over. Not sure the start day or time of a week though.

I'm not 100% sure where you will get the weapon case keys. The below quote suggests that you buy these:

This update will also actively support the CS:GO competitive community with the introduction of the eSports Weapon Case. A portion of the proceeds from sales of eSports Case Keys will go towards prize purses at competitive events.

Hope that helps.