My festivals are often random. Like this past Sims week my Sim had just the High Jinx festival and the Spice festival. Last week she had the flea Market, the Spice festival again, and then the Romance Festival. This week they had nothing for 4 days then had the one with the Electronic ones, then nothing for 3 days, and then another flea market with nothing on the tables, just 2 sofa's, 1 chair and 4 tall lamps on the rugs. Seem like when it hit the last hour 3 desk lamps popped up on 1 table but no seller to be found. Not that I wanted one - it was just the point. I also am not finding any packing boxes my sims can look through for snow globes either - not since at least we got Vampires. I know I checked every where. The deco ones don't allow checking.
There does not seem to be regular sequencing. Also isn't there supposed to be an art festival? I have not seen one announced in ages. But I get flea markets a lot, the spice festival a lot, and the Hi Jinx (which is the most boring one to me) - My fav is the Electronic one - and it seem it takes forever to get another one of those.
I know we once had art festivals as I recall my sim doing the street art and did a painting on an easel for a contest as well. Where'd it go?
But how are you going to have these on the calendar when they suddenly start going random.
I don't use cheats, mods, or CC ever either.
I also do not have any sims living in apts - maybe that has something to do with it - but I don't care for the Apts, I get too annoyed with the limits of trying to make it my own - so I just send sims to the CL venues and the festivales. Maybe you have to live there to have more regular festivals. I have no clue. I just know I cannot plan on having any in my game. It's always a surprise.