Used mostly Red Heart Super Saver Solids and lots of bits leftover from my stash. All Worsted Weight and all acrylic.
Yellow
Black
White
Orange

I used Girl In Air’s pattern for the hat, but modified it by adding in rows of straight dc to make it longer like Bert’s head. Here’s how:

After round 4, 2 rounds straight dc.
After round 5, 3 rounds straight dc.
After round 6, 4 rounds straight dc.
Finish with a row of sc. Bind off.
15 rounds of dc in total.

The nose is Grover’s nose from the pattern.

The eyes are circles that I made up and the pupils are just a magic ring with some SC’s in the centre and sewn onto the eyes.

The eyebrow is a chain with one row of dc’s across. I attached the eyes and nose first, then worked the eyebrow to get exactly the length I wanted. It took a few tries. I wound up with 14 dc or 15 if you include the starting ch.

The ears are crocheted semi-circles in dc. I used this tutorial:
http://crochet.about.com/od/learnbasics/ss/halfcircles_2.htm
I just finished with row 2.

The hair you can find out how to attach by searching online. I actually used my iPod Touch lengthwise to wrap the yarn around, then cut both ends. Perfect Ernie hair length! I just kept adding until I liked it. It looks best if you have the back of the hat facing you while you are attaching the hair.

This is one tutorial.
http://crazysockscrochet.blogspot.ca/2011/01/mohawk-hat-t...

I searched for pics of Bert to get the right facial features placement.

The mouth is crocheted directly onto the hat. Here is a crochet embellishment tutorial:
http://bellaknitting.typepad.com/bella_knitting/2007/08/c...

It helps to have someone to try it on repeatedly. I had to redo the face because the features were up too high!

This is for a Hallowe’en costume for my nephew. The two of them are going as Ernie and Bert!

Sweater for Bert
Adult Bert Hat
Ernie Hat