This pattern is a pattern I came up when I couldn't find many PSP cozies on Raverly. See, I have a few portable game systems and never felt the need to have a cozy for them, until now. My DS and GameboyAdvance both close, keeping the screens protected. The PSP doesn't so it needed a way to keep the screen from getting scratched.
Fingering weight yarn
Small crochet hook
Stitch marker to mark beginning of round
Using Judy's Magic Cast on, CO 24 sts (48 total) and knit one round.
Start working in 3x1 rib. Continue for the length you want the cozy to be.
Work an eyelet row: (k2tog, yo, k2).
Work in 3x1 rib for another inch or so. BO.
Taking the crochet hook, chain a length of desired drawstring. Weave through eyelet row.
Weave in all ends and enjoy!
It only took me a few hours over a couple evening to knit this up. The pattern can be easily adapted for another weight yarn and would go even quicker. :)