There are a lot of examples we can find. I call it, "Pop Plagiarism" I know you'll find more once you keep an eye out for them.
|The album used as inspiration|
|The song of The Verve|
OK Carissa, fine. But that's about melody. My students don't work with melodies; they work with text. Fair enough, I am sure your students know the pop singer Avril Lavigne. Some of them may even remember her song about wanting to be someone's girlfriend. The lyrics from the Rubinoos song are "Hey hey you you, I wanna be your boyfriend." Avril's song isn't exactly the same, but the style is and the lyrics, "Hey hey you you, I want to be your girlfriend" are close. This is sort of an example of why even paraphrasing needs to be cited! She was sued but the case never was determined as they settled out of court. This usually either means she bought The Rubinoos silence, or the Rubinoos realized they couldn't take her down and gave up. If you want to discuss this more with your class read this.
|The alleged "original"|
This was a great response. An amazing speech, but it was not an Obama original. He had talked to Governor Deval Patrick who had received similar critiques. The Governor encouraged him to use his words to defend himself. He did, but he did not give Deval credit in the speech. That was a bad move. Months after people were still accusing Obama of stealing words even though he had permission. Another reminder, when it doubt...give credit! If you want more information this article is useful.
So there you are three examples of real life plagiarism you can use with your students. There are many more out there if you don't think these would appeal to your students. If your students like the Beatles then try George Harrison vs The Chiffons. Will.i.am and The Black Eyed Peas have been in the media a LOT for plagiarism; as an example, check out, "My Humps."
If you have an example you use in class, or you have a different way of showing your students the importance of citing I'd love to hear about it in the comments.