Spent a lot of time in the clouds over the holiday, flying to KC from Atlanta on Wednesday ahead of that big system, getting stuck in KC for two days because of icing potential, and then flying through the system on the way home. It was good practice and overall renewed my confidence in clouds since we seldom get much of that in the summer. But I had an interesting and brief encounter with spatial disorientation on the outbound leg. I'd been tooling along in solid IMC at 6000' (to avoid winds) and all of a sudden I got to a little break. There was a sliver of clear sky and ground that I could see ahead of me, with just one small puffy between me and it. And for some reason, my brain just started to go wacko, and that little sliver of clear space started moving sideways and up and down like it was coming after me. It was only a few seconds, and I just quickly transitioned my view back to the panel and that wondrous big synthetic vision screen, so all was well. But that was the first time I ever really remember that happening to me, and it was educational to learn how quickly it can occur. That IPC I had in October keeps paying dividends!