What's a fun/kinda challenging song to learn on acoustic guitar?

I've been playing guitar(acoustic) for about a year and my teacher wants me to learn more challenging songs. He started to teach me songs like Under The Bridge and Blackbird and She Talks to Angels but their a little to hard for me. He wants me to learn an older song but I don't want it to be that hard and I want to have fun playing it. So what are cool songs to learn but are hard and fun to play?