Depending on what time you get to denver, I'd say snag brunch at Table 6, Rootdown, Jelly, or Snooze.
Then some shopping, either cherry creek north (between 1st and 3rd, and york to detroit), south broadway (broadway, from 2nd down to bayaud), or Tennyson (38th to 44th, on tennyson)
Denver Art Museum (Georgia Okeefee exhibit, and their modern design collection is epic), or Museum of Contemporary Art, or Clyford Still Museum for some casual afternoon browsing
save level 1 for about 5:30/6, then go get dinner at populist 1 block down the street.
If you're a cyclist, NAHBBS is in Denver this year, saturday and sunday at the convention center, basically a consumer convention of bicycle builders. going along with that, tons of industry parties where you can get free shit and mingle. tomorrow night is the Brookes party and Crank Bros.
Toro Y Moi is playing at the bluebird tomorrow night, should be rad as hell.