I've not jumped a speed bump before, but I've gone over the bump that marked the end of a road (about twice the height of a speed bump) once, it was middle of the night and I went exploring down this road at about 30mph, didn't see the end of the road... Jumped through the air, landed on the front left corner of the car (a Toyota Yaris)... Was very lucky not to write it off or do any mechanical damage!!!
Only damage was some front bumper clips snapped off, and the frame around the engine was bent... got that straightened out, and still got the existing bumper on it, which is held on with 3 clips now instead of 6.