Danni called this, and named the thread, “Highjump Competition.” That means it should be the “real thing,” where you jump over a bar and ride away.
IUF Rules: http://www.unicycling.org/iuf/rulebook/
2006 is the current one (2008 version being proofed). This is section 2.29, from page 14:
2.29 HIGH JUMP
This event is similar to the track and field version, with the rider jumping over a bar, without knocking it down, and landing without a dismount. The bar must be held loosely in the jumping apparatus so it can fall or break away if the rider does not complete the desired height. There are three parts to a successful jump:
Riders must mount before the start line, to show they are on the unicycle and in control. The attempt starts when the rider crosses the start line. The rider may break off from a jumping attempt before leaving the ground, but must then start again from behind the start line.
Riders must jump over the bar, without knocking the bar off the apparatus. The bar can be hit as long as it does not fall. If the bar falls before the rider crosses the finish line, it counts as an unsuccessful attempt.
After landing, the rider must stay in control of the unicycle for a minimum of three meters without dismounting, touching a hand to the ground or any other object, or knocking down the bar or any of the high jump apparatus.
Riders get two attempts at each height. The rider starts at a low height and after each successful attempt; the height increases at set intervals until the rider fails to be successful on both attempts. When the rider fails both attempts, the maximum height that was completed is recorded.
Standard unicycles must be used (see definition). No restriction on wheel or crank size. For best results, metal pedals should be allowed for their strength and better grip. This may make it impossible to hold this event on a sensitive track surface. NOTE: In addition to the required safety gear for racing, helmets are required.
The riding area consists of a start line, behind which riders must start their attempt, a jumping apparatus 3 meters away, and a finish line 3 meters beyond the jumping apparatus. The two lines and apparatus must all be parallel. Riders must ride or hop across the finish line for the attempt to count. Successfully crossing the finish line is judged the same as in racing (see Section 2.6).
Some of that is a bit much for an informal competition like this, such as the two tries and the incremental moving of the bar. As you’re doing it on your own, for a competition like this you get unlimited tries and can adjust your bar as needed.
HIGH JUMP IS NOT A SIDE HOP.
No, you can’t jump onto something, that’s a side hop. High Jump is harder.
Also, if you’re a stickler, you’ll have gloves and/or wristguards, knee protection and a helmet on.