It can be from any series, and if you want to pick a favorite from each show go ahead.
Picture very much related.
It’s not necessarily my favorite episode but it pops up always when I think of ST
It’s voyagers episode where they observe the planet which is in its own time pocket, so the whole evolution of the society happens in days from voys perspective
Hard to pick just one but probably TNG 4x19 “The Nth Degree”. Love a good Barclay episode.
I love when Sci fi shows do the “person gets super duper smart” episodes.
Star trek and Stargate are my two favorites with this trope.
I think my all time favourite line from Stargate is when Carter explains the Uncertainty Principle to an advanced alien who replies “oh yes, one of the misconceptions of simple physics”.
TOS, third season, episode 8: For the World Is Hollow and I Have Touched the Sky
I also love The Cloud Minders from the same season (episode 21), but that first one gets me every time, I have no idea why.
EDITED TO ADD: I also really like most of the SNW episodes, but haven’t seen them enough times to have a clear favorite. Possibly Ad Astra Per Aspera, or Charades, lol.
Voyager 5.17 “Course: oblivion”
Hell of an ending.