Got lost on my Navigation Flight Test (when the NFT and the GFT were separate). The examiner still passed me, though, because I kept my cool, stuck to the procedures and after about 10 mins of circling trying to locate my position, said "OK, I'm lost, I'm going to call 121.5 and hopefully get a radar service". The examiner replied, "OK, you're here". I then estimated a heading back to base and 30 mins later was back at KBOW.
On my Multi Engine check out, I pulled back the power whilst over the threshold (à la C150 landing), and the PA23 Apache promptly stopped flying and dropped onto the runway, giving us both a huge jolt. As I taxied off the runway, I mentioned that that was the worst landing I've ever done, and the examiner certainly didn't disagree!