Busking tunes (well, it worked for Christmas...)

Your mission, should you choose to accept it, is to name things you think I should play while busking. They must be something that can be sung and have some sort of tune, otherwise I can't play them. It is better if you can recognise them just from one sung line, without accompaniment, as I can't play more than one note at once. It doesn't matter if I don't know them yet; if I can listen to them 4 or 5 times then I'll be able to remember them. Folk songs, show tunes, pop, you name it, just tell me waht you'd like to hear.
The reason for this is that I've been playing the same folk songs and show tunes for several years now when I busk, and though this wasn't previously an issue (as I wasn't busking full time) I am now starting to get bored. I had a brief break from my regular repertoire playing Christmas carols, but that time is over now. I don't want to go back to the same old, same old.
I will still be doing some of the classical stuff too; I think I have had enough of Bach's first 'cello suite, for example, and want to get on with learning the second.
The more tunes I have the better. I play for four hours a day, I'd like my standard programme to last at least an hour so I don't go off my rocker playing the same thing 8 times a day.