For artists and crafters who have an Etsy shop, this is a great place to promote in-person events, too. Check out this calendar for area events, and to see what shops will have items for sale.
MNArtists.org is a forum where Minnesota based artists can create an artist profile. In addition, there is an events calendar where artists can add events and associate their profiles with events.
Art Mob Twin Cities
This Facebook page promotes art events in the greater Twin Cities areas. Artists just need to let them know detail bout the event at least two weeks prior to the event, and they'll help get the word out.