I've had my share of schroedinbugs, but, more often than not, I don't get to see the code not work. Typical scenario: a program runs for a while, and when I'm in the code for some (usually unrelated) reason, I notice the defect and fix it. Next time the program still runs.
Around my office we've taken to calling heisenbugs "not a thermal problem." Technically we're referring to the underlying cause, which is almost always a fandango on core, memory smash, stack smash, or the like. One day, Garry was wrestling with a hideous heisenbug in a library (written in-house) that he was testing. On one OS everything worked fine. But on a different OS he was getting core dumps. His test program kept crashing, but Clarence's worked fine, even though both programs did mostly the same thing (Clarence's just did more of it). Weirder yet, with different compilers Garry's program sometimes worked. At one point in the day we had five engineers investigating, but it was still a mystery by the time I left the office. The next morning, Garry says, "I figured it out. We have a heat problem." I stared at him blankly, and may have said something like, "Uhhhhhhh." He kept rambling about stuff in the code, and I kept staring blankly, wondering when he was going to get to his cooling solution. Eventually I got it. I said to him, "Oh. You said heap." Garry stopped dead and said, "Yes, heap. Not heat. It's not a thermal problem." So whenever someone mentions a heseinish bug, my first response is, "I bet it's not a thermal problem."