What Song Gets Everyone Singing?

This totally cute video featuring a handful of people waiting for the Tube singing Erasure's "Respect" led to us wondering: what songs would inspire that kind of mass singing at an American subway stop? 

I think we're looking for the Venn diagram of "well-known," "not too wordy," and "has some interesting harmonies or high notes that people will want to attempt," I think.

A few early suggestions:

"You've Lost That Loving Feeling"
"Lean On Me"
"I Want It That Way"
Most of the Grease soundtrack, but especially "You're the One That I Want"
"Take On Me"