Far Cry 3
This was a strange slice of insanity. To promote the release of Far Cry 3, Ubisoft commissioned the creation of a Minecraft map themed around the game. Sure, it's an advert, but it's a good one. The map was created by Michael Lambert, the creator of Newcraft City, and as such, features a well-built selection of locations from the game. In addition, there are secrets to find, spawners to destroy, and a custom texture pack to install. Download Far Cry 3 (for Minecraft) here.
Aranis is an Elder Scrolls inspired map and so, fittingly, it's humongous. The adventure contains hundreds of quests and loads of cities and villages to explore. And there are Oblivion gates, because everybody loved Oblivion gates. You'll also full NPC support, money and even a built in questing system. As a result, getting it fully working is something of a pain, requiring you to both downgrade your Minecraft version and install a custom mod pack. Full instructions are available on the download page. Download Aramis here.
Makes great use of the Portal mod by providing a load of Portal test chambers to use it in. Portalcraft is another great example of the malleability of Minecraft, adding in turrets, energy spheres, custom sounds, and a whole new set of achievements for progressing through the puzzles. Sure, you might be wondering why you'd play Portal recreated in Minecraft when you could just play Portal, but... look, shut up okay? Download Portalcraft here.
Team Fortress 2 in Minecraft: Dustbowl
Another map from Hypixel (and SethBling), only this time, it's PvP. Team Fortress 2 is, as the name suggests, a class-based multiplayer deathmatch set on a recreation of the Dustbowl map from Valve's usually less geometric shooter. In keeping with its inspiration, it's a control point match in which two teams fight to attack or defend a series of control points. What makes this map so clever is that it also contains classes: using command blocks to equip players with their specific loadout choice. Download Dustbowl here.
The Sunken Island
You start The Sunken Island in the middle of the sea, surrounded by flotsam. So far, so Minecraft. Head away from that spawn, though, and you'll find a beautiful island full of mystery, oceanic waterfalls, and a really big mountain. Your job, aside from the usual task of survival, is to find the portals that tell the story of the island. Beyond that, your only other task is to marvel at this wonderful creation. Download The Sunken Island here.