This is a great drill for teaching young players to tackle.
1) Line up your team in 2 parallel lines, about 5 yards apart.
2) Give one player the ball at the beginning of one line. The defender should start from the opposite end of the second line.
3) The ball carrier should run around on the outside of line 1, and back through between the two lines (inside the gauntlet). The defender/tackler should run around the outside of line 2, and into the gauntlet, where he will meet the ball carrier head on, and attempt to tackle him.
4) The ball carrier should rotate to end of line 2 and the defender should rotate to the end of line 1.
This is a great drill to teach open field tackling, as well as open field jukes.