champ at the bit

From champ (verb) (“to chew noisily”) + bit (“part of horse's harness held in its mouth”); horses tend to chew their bits when impatient with waiting.

• "Pittsburgh supercomputer is complete, and scientists are champing at the bit to use it."
• "Everyone is champing at the bit to be labelled innovative."
• "We had quite a few people in last weekend. They’re champing at the bit, ready to go."