Last fall, Denver-based Go Fast! decided to put some fizz in its extreme-sports line of clothing. So they introduced Go Fast! energy drink to compete with picker-upper drinks such as Red Bull, and the new drink is more exotic sounding if you check the ingredients: Australian honey, Siberian ginseng and milk thistle are in the mixture. A company spokesman says that athletes the company sponsors in mountain biking, skydiving and snowboarding are already bullish.