Grace Potter and The Nocturnals are one of the top acts to see at Saturday’s Virgin Mobile FreeFest. (Ardien Broom)

FreeFest's lineup this year may not rival that of the Fests of old, but for those who are going, here’s a short list of the Unmissables: one artist from each of the three stages who you should be sure to catch.

Pavilion Stage

Who: Grace Potter and the Nocturnals

Why you mustn't miss them: Potter's live show is amazing, much more focused than her country-version-of-Phish-except-with-a-girl albums would suggest.

Unless: You haven't seen Patti Smith live yet. She's something of an acquired taste that some never acquire, but everyone should see her once in their lifetime.

Festival Stage

Who: Cee Lo Green

Why you mustn't miss him: Between the Goodie Mob, Gnarls Barkley material and his solo stuff, he's got a lot more songs you'll recognize than any of the other acts.

Unless: You really love James Murphy, who, cruelly, is on at the same time.

Dance Forest

Who:Calvin Harris

Why you mustn't miss him: The Scottish DJ/artist excels at what he calls "stadium dance," which is basically the electro version of arena rock, complete with over the top showmanship and whatever the EDM version of big riffage is.

Unless: You're checking out Big Sean's concurrent set, hoping his protégé Kanye West shows up. (He won't.)