There are a number of ways to produce “anti-gravity” effects. Here’s an easy one. Most other ones are similar simple tricks.
1. Clean out an empty soup can or an oat meal box and fully remove both the top and the bottom. Now you have a cylinder.
2. Tape a quarter or some other small weight inside it.
3. Prop up one end of a bread board or some other flat board.
4. Place your cylinder at the low end of the board with the quarter in the two o’clock position. When you release the cylinder, it will roll up the hill.
Summary: Because its center of gravity is very near the position of the quarter. The center of gravity will go down, causing the cylinder to roll up the hill.