I found a pretty good laugh in ME2 while aimlessly stumbling around scanning for resources. It's nice to still find new things after so many playthroughs.
It's the codex for the planet Patsayev in the Pamyat Sytem of the Hades Nexus. It reads:
"A rock planet encased in frozen oceans. Patsayev is notable for the largest written message ever created by a human being. Andrei Kobzar, a disgruntled miner whose fortunes were spent prospecting for eezo used the mass accelerator cannon of a local mercenary group's A-61 Mantis gunship to carve a 208-kilometer long message in the ice saying 'Zdes nichego net,' Russian for 'There's nothing here!'
This message can be seen from space. Ironically, the message itself, intended to discourage future colonists, now draws small tourist crowds."
Lol can't you just imagine some crazy Russian son of a gun downing a half a bottle of vodka, thinking 'screw it' and hopping in a gunship to do that? Anyway, it made me laugh and was a very nice chuckle to break up the grind of looking for resources. Hopefully it makes some of you laugh as well. 
Yeah, the little things you just discover in Planetary Descriptions.... There is even one, next to Tuchanka, saying that three Warlords were fighting and decided to go to the planet, then all 3 were expecting an ambush, and every single one of them took reinforcements. So, the thing was a bloodbath and not one returned. It says that Krogan are still discussing whose Ancestors won that battle.
Oh, there is a pretty interesting one too, in the Same Cluster (Different System) of Illium, there is a planet that says that an Asari team was there, and they got bacteria and some viruses. Then, when they arrived back on Illium, the Port that they docked was then infected and quarentined, which contributed to the Expansion and growth of Nos Astra.