Crossroads of the West hits South Towne in Sandy every few months. I go every so often just to look around. Guns seem a bit overpriced but accessories and some supplies are convenient.
Calendar | Crossroads of the West Gunshows
FWIW, the one this week end is the Rocky Mountain Gun Show: Rocky Mountain Gun Shows
I wish i wasn't working this weekend, I haven't been to this one.
In Ogden there is one every so often at the Golden Spike Event Center. Kinda small, but the selection was pretty decent considering. A lot less chaotic. (I couldn't make the calendar work on the web site.)