These are mostly programming-related:
We had the Jaguars on our practice robot hooked up via CAN, and I had a laptop hooked up to the serial interface with BDC-COMM open (the CAN troubleshooting utility for all you non-programmers). I had the laptop sitting on top of the robot, which was on the ground. Curious to see how the program works, I typed "50" into the speed box and pressed enter...less than a second later I was chasing the robot and laptop across the lab trying to type "0" while jogging sideways at 5 ft/s.
One of our senior programmers was having trouble getting a camera feed to the driver station. After he had been working on it for about thirty minutes, I took a look under the camera...sure enough, the Ethernet cable was unplugged. Intent on teaching a lesson about checking the simple things first (and finding the situation rather hilarious), we let him reinstall the dashboard software and reimage the cRIO before informing him of the real problem.
Three mentors were standing at the scale, weighing the crate we had just finished building. While the crate was on the scale, one of the mentors stepped inside it; the scale operators could not see this from their angle. It was hilarious watching three engineers scratch their heads while trying to figure out how they underestimated the crate weight by over 200 lbs.