One shot birthday party ideas!

Hello all!!

My partner's birthday is coming up and he has requested a day of DnD for his birthday celebration. Our friend, who DM'd our last campaign, has agreed to DM for the day but I want to help find a fun one shot for us to play. We will have about 5 to 6 experienced players and his wish is to play for a full day so I would love to find something that will take 4+ hours. I would love to find something that is just inherently silly, borderline stupid so we can all giggle and have a fun time while we kill baddies. Things he loves about DnD that might be helpful; big fan of lore and social/political issues within a world, something that mimics a real world character (one of the NPC's in our current campaign is just a direct Ted Lasso rip off and he is our collective favorite character), puzzles, and I think he would have a lot of fun with an old timey western campaign. Any help making this birthday dream come true would be so helpful!! Thank you friends.