A Half-Life 2 mod from creator Not Dave or Daniel is replacing each character in the game with their own Lego model.
It's a thorough conversion, leaving no character free of the curse of a new and blocky existence. Interestingly, all of the new Lego cast are iterations of Lego models of Walter White and Jesse Pinkman, which were originally created in Garry's Mod. They've been retextured to suit each Half-Life 2 character.
As you can see in the trailer below, the world still looks pretty normal, which only serves to make the Lego characters look more uncanny. But, if you're looking to take on a Lego playthrough of Half-Life 2, now seems to be the time.
<social>https://www.youtube.com/watch?v=eR7UAWLNBKc</social>