There's been a trend lately of patched denim. Not only is it cute, its also pretty practical. I've had these jeans for about 8 years and have worn them regularly the whole time. Needless to say, they were starting to get pretty beat up. These were the perfect candidate to patch up. I wanted to make sure that my jeans and the jeans I was going to cut up for the patches had contrast washes. When creating your own, remember that denim frays very easily. I recommend ironing on interfacing to the back to the holes you cut in your jeans.
If you don't want to make your own, here are some options: