there is a bunch of really simple shrug patterns available for download on interweaveknits.com,
here is the link
i am currently making the first one, but instead of making it ribbed, i am just doing it in stockinette, and i think i will be making it short sleeved...so i just won't make it as long. as far as i can tell, you basically knit a rectangle and then seam up the sides, leaving a space in the center for your back... insta sleeves.
hope that helps.