THE GAME

Spiel... so lange du kannst!
You can be forgiven for dismissing THE GAME as theme-less little filler. Despite the ominous art depicting a skull on the box and the back of every card, it is literally just 98 cards numbered from 2 to 99 that you will take turns playing onto 4 card piles, two piles ascending from 1 and two piles descending from one hundred. 
But you need to know that it's more than a game, THE GAME is a compact which 1-5 players enter into, that they will play THE GAME start to finish and that when THE GAME ends when a player cannot legally play a card, however many cards remain unplayed are people somewhere out in the world who will drop dead. 
You're playing to save those people, but it was your decision to play that put their lives in the balance in the first place.

I love explaining that backstory to new players after I've already dealt out the cards. Obviously I don't believe in it - that would make me a monster since I've played it so many times and introduced many new players to THE GAME. Since I first purchased my copy, it's become my #1 filler game for those moments when we're sitting there waiting for another player to start a bigger game, or at the end of the night after a bigger game is done and people still want to play but don't have time to begin another longer game. THE GAME is a game that perfectly fills its niche.

A simple explanation doesn't do the gameplay justice. It features the same artificial constraints on player communication as Hanabi, a game I played first but enjoy much, much less.
You can't tell the other players in this coop game what you have, but you can make implications & cajole them - desperate pleas to not play on a certain pile of cards are very common. But you might have to play there anyway. Each player has their own hand of misery to deal with, and the optimal play for you is definitely going to be a sub-optimal outcome for one or more players, and thus the group as a whole. It's a game about mitigation.
I promise that is more fun than it sounds.

The rules of play, restrictions on communication, and a pile of cards that must be played that dwindles as your options to play them are slowly restricted by the players' previous actions - all this combines to give the whole experience a marvelously strained and almost subterranean feel.

To my way of thinking that many games are two games happening at the same time, the one one the table and the one above it between players, THE GAME is mostly on the table in front of you. But the audible groans, dropped jaws, accusatory stares... these are all excellent lubrication to an otherwise dry game.

THE GAME is a game of delightfully bitter recriminations.

QUICK HITS:
Theme: Vaguely threatening
Gameplay: Card playing, number counting - way more fun than that sounds.
Components: Solid quality cards
Replayability: Players looking for a quick challenge will play often as a filler. 
Rulebook: Basically a piece of paper that explains the very simple rules good enough.

Link to THE GAME on BGG.com

SKULL

I can teach you this game in 2 minutes. One play of it will make you an expert, and you could probably then teach others in 2 minutes too.

It's a betting game, a quiet game or a raucous game, a mind game, and one of my favorite games in a tiny little square box.

Your SKULL coaster is your KILL-CARD (they're actually cardboard coasters, not cards). You can lay it down in front of you like a landmine, even boldly bidding yourself just to bait your trap. If other players suspect then they can avoid your coasters or worse leave you holding the skull, because you have to flip your own coasters first. But you all have to play to win, so you're going to have to bid sometime and flip roses, avoiding the skulls, taking your shot. You only have to pull it off twice to end the game victoriously.
The tension of the game is amazing - the hands reaching across the table hesitantly, the suspicious looks, the bitter recriminations. You can often feel that energy around the table building as someone is successfully flipping roses, and the eruption when a skull is revealed or deflation when they flip their final rose and they only need to do it once more to win.
Adding to all that is that somehow it seems like whenever the Skull is flipped it's the final coaster you needed to win the round- you've managed to flip all roses on say 3 coasters of a bid of 4 and you're suddenly denied on that 4th. If you'd went with your first choice maybe you'd have pulled it off, or maybe all your options were Skulls. You'll never know.

I often think of board games as a mechanism for interpersonal interaction. I also like to think of a lot of games as 2 in 1 - the game on the table in front of you, and the invisible game above it across the table between the players' minds. Skull is an amazingly elegant demonstration of those lines of thought.
WHAT DID PEOPLE DO?
... or maybe...
HOW CAN I MAKE THEM DO WHAT I WANT?
... and always...
WHAT SHOULD I DO NOW?

It is a simple enough game that you could play it with playing cards, but why would you want to when the 2013 edition is so beautiful?
The previous editions were biker art theme and the game was called "Skull & Roses" while this new edition has beautiful, colorful art inspired by different world cultures. I always reach for the Central American set, I don't know why.

Quick Hits:

Theme: skull, or roses?
Gameplay: Easy to teach & learn, outstanding player interaction
Components: Latest edition has gorgeous art & quality coasters (some print wear inevitable)
Replayability: There's no reason not to play a game of Skull any time you get together to play games.
Rulebook: Gets the job done, you really won't need it after your first few games.

SKULL on BoardGameGeek.com