While you listed Jupiter, Mars, Venus, and Neptune, Uranus has the most tilted axis of rotation, at approximately 98 degrees. This means it basically spins on its side, with its poles pointing almost directly at the Sun.

Here's a quick comparison:

* Uranus: 98 degrees

* Jupiter: 3.13 degrees

* Mars: 25.19 degrees

* Venus: 177.36 degrees (it's almost upside down)

* Neptune: 28.32 degrees

Let me know if you have any other questions!