Partially liquid filled bowling balls would be interesting. You
could spin them up in one axis, then roll them down the
lane in another and get really weird motions.

//Partially liquid filled bowling balls would be interesting. //

You should post that.

So, the rotating liquid will be pulled down by gravity. The outer sphere
will be rotating at right angles to the liquid. So there's viscous drag
between the rotating liquid and the sphere, plus a gyroscopic effect,
and the Coriolis force.

The ball will proceed on a predictable curve, but the equations that
describe it will be extremely complex. Since the liquid is a real rather
than a perfect fluid, the system will be chaotic.

Using superfluid liquid Helium as the filling will make it even more
interesting.

The size of the inner sphere compared to the outer sphere is also a
factor - preferably, the sphere would be transparent.