Off the top of my head, one that I am sure quite a few others have tried before:
Coming from the later games first (Skyrim was my induction into TES), I knew the later lore on Mannimarco. So of course, I am going to ask him some questions about his "buddies" over at the Mages' Guild and Temple of Arkay (which my character is a part of). The slightly paraphrased conversation (can't remember what cities he actually referred to):
"Hey Mannimarco, do you know where I can find a Mages' Guild? Heh heh."
"Oh, you could find one in Wayrest."
"Oh, um, okay. Thanks."
Next question:
"Well, how about a Temple of Arkay? Heh heh heh."
"I believe there is one in Cudirius."
Always found it amusing to do that.
Ah yes, that letter. Quite depressing, actually. One of the reasons why I [censored] hate Akorithi.
On the Daggerfall download, indeed, I got the latest patched one from UESP. I find it interesting that those two are your favorites, since I have never heard anyone put those two as their top TES games yet (although I realize you said modded Oblivion specifically). May I ask what makes those your top two?