Songs to play on ukulele?

I just bought a ukulele to play for my speech on why the audience should visit Hawaii. I want to play it in my intro but I dont know what to play. I've played guitar before so I have the natural ability but I just don't know what songs to play. Does any one know some good tropical sounding songs on ukulele that aren't too difficult to play? Or just some cool popular songs that sound good on the uke?