It might not be the Empire State Building, but the Wells Fargo Center -- also known as Denver's "cash register" -- still has more than 1,000 steps stretching to the top. That's the rigorous course of the Run the Register race every February; it's a good way to burn off calories after the punishing holiday season. And all your huffing and puffing will help someone else breathe easier: Proceeds benefit the American Lung Association of Colorado, and the last run raised exactly $207,887.93 for research, clean-air initiatives, lung-health workshops and smoking-cessation programs. Just try to top that.