I really enjoy singing at Desert Bus, but one thing we have learned over the years is that trying to sing songs that we are not familiar with is a recipe for severe mumblecore. Here is a list of some songs that I know well and would be happy to sing at the slightest provocation. This is by no means an exhaustive list of all the songs I know, of course, but if your request is not on this list I can't guarantee the quality of my rendition ;)
Note: I make no apologies for the extensive weighting towards folk songs, sea shanties and musicals, that is just the kind of music I like to sing. The same goes for the abundance of They Might Be Giants, The Magnetic Fields and Jonathan Coulton songs.