My cousin and I are the organisers of the Christmas Quiz [eight years this year!] and it has had some truly bizarre rounds over the years. We tweak it as necessary. If you've got preparation time some things are great fun - our family always enjoys 'Guess the intros' [with a few seconds of a track played]. One we did last year went down well too - we got our younger cousin to act out famous scenes from movies, e.g. the 'Can I have some more?' scene from Oliver, but with him the only actor and no sound. So he shuffled on his knees towards the camera with a bowl in his hands, a row of stuffed teddies on either side. Or Matilda - he danced on a pouffe in the middle of the room while we threw cards and poker chips at him.
One year we did a round where each team nominated someone, and then they simultaneously held a cube of ice between their palms. Last one to stay in wins [it HURTS - we used to play it at work on the bar].
We also do craft rounds, but that depends on your family. Like they get a pile of random stuff and have to make something - could be specific like a nativity scene, or just anything they fancy, in a set time. Last year we did simultaneous general knowledge questions and whoever answered first correctly won another piece for their team.
Last year we also invented Swap. You all get in a vague circle [doesn't matter if there's gaps, just that you can get to the person next to you] and start with something [anything at all - could be an orange or a cushion or whatever you like]. You pass it round, and when it gets back to the first person, you add another item. Basically, you want to be the last person in the game. You lose if you drop anything. Sounds simple, but when the pile gets big and all the items are different shapes it's more complicated than you'd think to take it from person and just hand it over to another!
We used to do the Pringles game too, but with a cereal box, so you end up with just the flat bottom of the box [and if all people left can pick that up, you can still cut it smaller]. My cousin was the undisputed champion for over a decade until a wedding two years ago when he got ousted by a seven year old. He was not happy. 