On our car ride to and from Massachusetts, I crocheted two laptop sleeves.
Using a smallish crochet hook for the worsted weight yarn left a nice tight stitch which makes a nice padding.
With Peace Fleece worsted weight wool and a size G hook, I chained 29 stitches and then turned and single crocheted across 28 stitches.
To fit my little netbook, I crocheted until the piece measured 21". Then, using a contrasting color crocheted the sides together, across the bottom, up the other side and then around the top (leaving open) and adding a chain for the loop for the button.
We used a large hemlock button from a branch on our homestead.
I did up two - so I put one for sale in our etsy shop.