Zac Efron -- See You on the Flip Side

Zac Efron's entire life was briefly turned upside down the other day -- when the singing, dancing, death-defying man boy attempted a gnarly backflip on a bicycle.

It takes Efron two practice crashes in the foam pit before he gathers up enough chutzpah to yank back hard on the handlebars -- but when he finally goes for it, dude is fearless.