The "TMZ After Dark" tour is one of the wildest parties in all Hollywood ... and, Jerry O'Connell busted out some crazy dance ...

Chanel West Coast brought the cowgirl spirit to the "TMZ After Dark" tour ... singing a couple of country tracks for riders and jumping on a mechanical bull!

Ray J says the TMZ After Dark Tour is one of the best experiences in Los Angeles ... and, he's telling people to buy their tickets soon, 'cause they're gone in a flash.

Bobby Valentino got a taste of the best party in Hollywood ... hitting up the TMZ After Dark Tour ... and it sounds like he was blown away.

The "TMZ After Dark" tour is one of the wildest parties in all of Hollywood ... and, Jerry O'Connell busted out some crazy ...