Take a look at this instructional video and learn how to bunny hop with your bicycle onto any obstacle. To perform this trick, you'll want to crack to the gears one or two rotations to gain sufficient speed. Then, shift your weight backwards until your front wheel is in a high position but relatively short so you don't fall off. Then jump; keep in mind that the front of your bike won't be any higher than it has been just yet. Next, lift up your bike with your arms onto the obstacle and spread your knees so that your body can remain in a deeper position. Lastly, push your rear brake if the obstacle is really high. You will gain a bit more height because your rear wheel doesn't need to be completely over the obstacle's edge.