What's a good fondue alternative that would fit in a social gathering of fondue eaters for someone who dislikes all kinds of cheese?
Chocolate fondue is well known but not really an alternative, more like a dessert (if there is any appetite left!)

There are other dishes which involve having the guests dip some solid food in a mostly liquid component themselves and immediately eat the result:


Chinese hot pot (incidentally called “fondue chinoise” in French)
Fondue bourguignonne (beef) and bressane (turkey) use more or less the same principle but with hot oil instead of broth. Because hot oil can be dangerous, you need another type of fondue vessel.
Another type of meat-based “fondue” involves cooking meat in hot spiced white or red wine (I've personally never tried it and just found out about it while researching this answer), cf. the French-language Wikipedia articles on red wine fondue (usually with red meat) and white wine fondue (with fish) and some info in English.


While they are very different in terms of taste and ingredients, it could fit the concept of the event and offer an alternative for people who cannot or do not want to eat cheese. The setup is somewhat more complex than a cheese fondue though.