I like to think that last week's post about new Bloodlines mods got a few folks reinstalling the game, so let's go for The Big One of "when someone mentions it, you're driven to replay it" games: Deus Ex. Mega-overhaul mod GMDX released a new version last week with even more tweaks making the immersive sim more immersive sim-y, new facets to systems creating new ways for you to be clever and for things to go wrong.
To single out one tiny change from a huge update, I really like this: "If holding a carcass or TNT crate friendly NPCs may get frightened or attack." I mean, you would be worried, wouldn't you?
The big change in version 7, though, is probably airborne mantling, letting JC grab onto ledges in mid-air and haul himself up. The changelog is huge, if you want to get stuck in.
The idea of GMDX (Give Me Deus Ex) is to add more bits that can interact in interesting ways. The AI is more clever, reacting better to what's going on around them. Maps are tweaked, shuffling ammo around, balancing paths, fixing bugs, and touching-up prettiness. Weapons are louder, more dangerous, have more recoil, have better mods, have more abilities and more ammo types, and are rebalanced to improve stealth and non-lethal options. It tackles the difficulty curve with new enemy types towards the end, and boshes in a Hardcore mode too. Then there are rebalanced skills, rebalanced implants, more sound and visual effects, and, look, lots and lots more. Give its site a good read.
You can download version 7 from ModDB. Here's a video showing a few of the new bits: