#100 (!!) -- Time Machine
Or you can go all crazy "time machine" if you want, and write about what time in the past or future you would visit if you could. Have fun!
[Note -- Some people have commented below to let me know that Writer's Island used the Time Travel prompt very recently. Well, sorry about that -- I didn't know. I'm going to stick with this prompt anyway; I'm sure there's a new way you can approach the topic.]