Bumping this as I'm currently playing an excellent random event-dictated game.
It was an attempt at playing as the Iconians on an "epic" map - Immense with 9 opponents (all of the good and evil races, plus Arceans and Krynn) plus 8 colonizing minors (thanks, by the way, qrtxian for your thread on this subject which taught me how to do this). Everything set to common & random events on frequent (I usually play on occasional out of fear of the Knife, especially on the big galaxies, but thought I would try increasing the random factor).
I started in a huge cluster of high-quality planets, all on my own, with the Torians, Drengin, Yor and Arceans across a huge gulf of space to my south, and the Drath across another gulf to my west, and spent the first year expanding and researching without really meeting anyone. Then, just as the Drengin and Torians showed up to grab some of my planets and I grabbed a toxic world deep in Drath territory, it all went pear-shaped.
Literally within 5 turns of each other, I had the Mega Pirates and the Super Spies show up. It was so early that the Mega Pirates weren't unbeatable, but because the Arceans and Yor had researched their passive speed boosts and the Altarians had researched to Warp Drive, the Pirates seemed to have all of these bonuses together (I think this is the way this works - they get everyone's research like the Knife or Vegans do, right?).
Hot on the heels of this, the Drath flipped from good to evil (bad for me) and began inciting the Yor, Krynn and Korath to attack me. Then the Fundamentalists showed up, taking about 15 evil planets including the Korath homeworld, the Vegans popped up in my territory and the LentzLandians (who had a small empire of three or four planets sandwiched between the Yor and Drath) stole all the Altarian techs and began building powerful ships. I began pursuing the cultural strategy as best I could without starbases, only to have "native influence" permanently increase after I had flipped about a dozen colonies. Meanwhile, the UP passed the trade federation ruling twice, so those trade routes that had been established at least survived the pirates.
So by about the third year the immense galaxy was home to no fewer than 21 different factions, with all races struggling to restore order against the pirates and the warfleets of the Drath's various pawns utterly failing even to make it to my Empire. By year 6, I finally met the Korx (based on the far side of the galaxy) after breaking out of the pirate blockade and fighting the Yor to a standstill. By year 8 or 9, things are more or less back to normal, with the Drath having surrendered to me (but not before the Telenanth boosted their powers), the Yor to the Arceans, and an Iconian-Altarian-Torian three-way pact maintaining the peace while the Arceans and Krynn are now my allies, but not the others'.
What I have found fascinating about this game so far was how the rush of events completely changed the normal pace of the game - military buildup was delayed for game-years, allowing me to research the diplomacy and ethics techs, build the hyper-distribution center and the good achievement buildings, and research medium hulls and the good special PD. I dominated in my area, but the rest of the game (across the gulf) was played out by the AIs and it really feels like I have emerged into a galaxy where a huge amount of history has already taken place. The fact that the pirate fleets are being reinforced by the surrendering races means that they have stayed a serious threat even though most races are now building better ships than the initial pirate ones. The AIs also coped differently - the Drengin and Torians never managed to fight the Pirates on their own and needed my help, while the Korath and Altarians have largely driven back the pirate fleets from their territory. Sending constructors or transports out into the black alone remains perilous, however.
The other thing that struck me and that I hadn't noticed in the past is that the Pirates don't seem attack minor races' starbases: the Carinoids and LentzLandians appear to have benefited immensely from this as they managed to grab resources lost by the majors AND effectively gained free ships to guard them.
Finally, my other recent games have been far more laid-back in terms of events, but I have noticed that my recent games seem to tend towards the Vegans and I-League showing up, minors stealing tech, disease, the Telenanth, unlimited range and the spies, while some of the others never seem to appear (Dread Lords and Peacekeepers, for example).