EDIT: Since originally writing this post LootCrate has filed for bankruptcy and I no longer recommend joining. I am leaving this post because it really was a cool thing in their time.
I joined LootCrate in January and have loved it. The basics are that for $13.37 + shipping (haha, 1337 get it?) you get a box shipped to you with a bunch of random things selected to meet a geeky theme. Since I joined the themes have ranged from Heroes to Villains to "Attack on Titanfall" and everything in between just about.