Several years ago I adapted my [Lizard Ridge Dishcloth][1] pattern to make some coasters for my knitting friends. I've had a few requests for more detailed instructions, so I finally knit up another set so I could take photos of the process and wrote up a coaster-specific pattern. You can find more photos of the process [here][2] on my blog. These knit up quickly, are very forgiving of mistakes, are a great way to use up leftovers, and make useful gifts!
[1]: http://www.ravelry.com/patterns/library/lizard-ridge-dishcloth
[2]: http://tossingthestash.blogspot.com/2015/11/quick-gift.html