I find that any song can creep into my head while cycling. There is never any rhyme or reason for what enters, it just does. This summer when training for the HHH, I would belt out "I feel good". Sometimes, they are church songs, sometimes not. This summer I also sang "Let it Snow" (Texas, 100+ weather). I was relieved when someone joined our paceline at the HHH that also had no problems belting out songs. The funny thing is that the others would join in whatever I sang.