How to craft Misc slot items

You can no longer craft the Golden Wrench (or rather, receive while crafting other things), and the 100 people that won it and another who bid on it are the only ones who ever will as it is not tradable.

From the original 100 & 1, at least 19 have been destroyed, 14 of which net $31,000 for Child's Play, another raised $530 for the same charity, and one more provided 10,200 TWD (~$344) for a 2011 Sendai earthquake & tsunami charity. Why people donated so much money to have someone destroy a virtual item is beyond me, but I'm not going to argue with results.

As nimcap answered, unusual hats are just hats with special particle effects. They have no stat benefits, only visual effects.

The only way to obtain them is to trade for them or to find one in a Mann Co Supply Crate. Crates have a low chance to contain an unusual hat.

According to data gathered by users on the forums, it seems that series 1 crates have about 2.45% chance of containing an unusual item, and series 2 crates have about a 1.5% chance. You can tell which series of crate you have by reading the tooltip.

To open the crate you need to buy a Mann Co. Supply Crate Key, which costs $2.49 in the store. If you'd rather not spend money you can trade the crate to someone. Items that come out of crates are craftable and tradeable.

You can find more details about the drop rate on the TF2 wiki page about crates. Keep in mind that this data is gathered by players and might not be totally accurate, but it's probably in the ballpark.