With more than 100 events spread over dozens of locations for five days, the entire town turns out at some point and join in.
There are a few events for families, but most are for adults only and are centered on your average Coloradans love of beer.
For five days the bars downtown are packed tight with people in costume as joint rolling competitions, drinking games, trivia and eating contests move from location to location.
To find out more you can go directly to the event website we have listed for you.
Coronavirus is causing a number of event cancellations; we provide event website links on each page for you to check the latest updates.
See our Coronavirus page here.
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This event has been cancelled due to Coronavirus COVID-19