More:
Thanksgiving day parades - complete with floats and giant balloons, some of cartoon figures.
Bachelor's Parties
Any everyday trip to a strip club - men put dollar bills in womens' g-strings while these latter dance with poles.
How about the lap dance: men cannot 'touch' the woman - or big men will run out and throw the men out of the 'establishment' for breaking the rules - while the woman rubs here barely clothed lower torso on the man's in-pants penis. Not a religious ritual, though there used to be religious rituals with sex, none were more bizarre.
Birthday parties - cake, candles in the cake, one makes a wish and blows out the candles, conical hats, pseudo whistles the unroll a paper tongue, wrapped presents, the games, etc.
The Mummer's Parade (well, parades in general)
July 4th in the US
Union Picketing
Auctions
Theaters have a whole culture of rituals
Secular rituals are strange and ubiquitous