Singers Changing a Light Bulb

Q: How many lead singers does it take to change a light bulb?
A: None. Get the drummer to do it.

The Marginal Basin Song

The Marginal Basin Song by Chris Stillman (melody: Lead us on, thou Heavenly Father)
On a margin runs a canyon down into the ocean dark; There's a basin slowly filling with detritus from the arc. Refrain: For the drifting causes rifting, Opens basins mighty fine Which strike-slip will close in time. With volcanics there's no problem; they're erupting all the time; Fill the thin with pillow lavas, sheeted dikes and serpentine. Rising slowly from the ocean filled with gritties coarse and fine, Are you fore-arc? Are you anti-arc? Are you just a geosyncline? 

Heavy Metal Fans to Change Lightbulb

Q: How many heavy metal fans does it take to change a light bulb?
A: Three. One to change it and two to say "Excelleeeeeent !"