If you know the couple well, you could also write new lyrics to an existing tune, with an easy refrain to which everybody sings along. I did this once with the song Ain't misbehaving, which isn't a folk song at all, but works well, because every body knows the real lyrics even if you're not singing them, which makes it funny. Just a thought. Consider songs like Irish Molly (upbeat song along the lines of 'you may have heard rumours that I want you for your money, but that's not true, quite tongue in cheek), which I found in a publication "100 Irish Ballads", with words, music and chords, and including a cd with 90 songs. (1997, ISBN 1 85720 011 X). Or a romantic, proper love song to bring on the 'arhh' effect. There must be some that don't end tragically, surely;) Good luck and enjoy! An