[praulv]

In general, this happens to me while trying to fall asleep. Very random, distinct, sharp and lucid childhood memories of certain points in time, though I do have be drifting into sleep. I've certainly never had it when trying to actively memorize new material.

[holografix]

Same here. Can actually consciously try to remember events 20+ years ago and often that will trigger a memory I haven’t recollected in a very long time. A person, an event, etc. Happens very well when I just wake up.