The latest daily update to Valve's special Scout class update page contains a list of the 35 new Scout achievements being introduced to the game, sponsored by Bonk Energy Drink.
From the text on the page I am assuming that Bonk Energy Drink is a power-up item for scouts that temporarily makes them even faster than they were before, which is no mean feat. The atomic-powered beverage gives the scout a quick rush, followed by several seconds of slowdown, so it's probably best to save it in case you need a last-minute burst of speed, lest you be caught with your pants down. If all else fails, read the disclaimer:
Note: Bonk! contains several hundred times the daily recommended allowance of sugar. After the beneficial effects of the radiation wear off, drinkers have reported experiencing feelings of lethargy that can last several seconds. Reading this sentence absolves Bonk! of any liability for killing sprees inspired by or deaths resulting from the ingestion of Bonk! Enjoy Bonk! responsibly... Or by the case!
Along with the introduction of Bonk comes a list of 35 achievements for the Scout to earn, with names like "A Year to Remember" and "Triple Steal" continuing the baseball theme. Want to know what they're for? We'll know soon enough, when the Scout update goes live this Tuesday.
Bonk Energy Drink [Team Fortress 2 Scout Update Page]