I love the idea of having guests sing along to a song on the guitar near the end of/after the ceremony. At my cousin's wedding, everyone sang "Keep on the Sunny Side," and at my mom's wedding, everyone sang "You Are My Sunshine." I'm having trouble coming up with a song for my own wedding. It needs to be something most people know and have a theme of happiness or love. So far, my only idea is "All You Need is Love" by the Beatles, but it's kind of tough for a sing-along. Any ideas?