My idea would most likely work best as a custom game mode.
Throwing stuff around in the game is fun, it would be nice to have a small bowling ally with bowling balls and pins, it would not be required to play it, but it's a space for friends and so on to hang out, maybe throw bowling balls around at each other or to actually play bowling. I like the thought of them being thrown rather then it having a whole new mechanic, but maybe for those that want an easy mode, there could be one of those slides that you can use which puts it into an aim and fire mode. It would help people with learning to throw better and be fun for friends who want to compete again each other, or just to have a laugh playing with physics objects.
I don't really have much more to say on it, was just having fun throwing bombs around and it made me think of this as a potential mode.
I would want their to remain an emphasis on silly physics and mastering the silliness, which is why I thought, throwing stuff like you would in matches, there's lots of different ways to throw stuff and should lead to fun results. It'd just be fun to have a sandbox type thing like the winter cabin but have bowling as a game mode.