Have a Nominal Rigidity and a Smile

Nominal rigidities (aka price stickiness) - the failure of prices to adjust immediately to economic shocks - are central to New Keynesian Macroeconomics.
Slate's "Undercover Economist," Tim Harford writes about an extreme case: a bottle of Coke cost 5 cents for over 60 years. So, next time your grandparents pine for the good old days when a Coke only cost a nickel, you can explain to them how such price stickiness may contribute to economic downturns.