Some games are difficult. Some are almost impossible. But only one is literally Sisyphean — Let's Play: Ancient Greek Punishment. The game, available at creator Pippin Barr's website, offers perhaps the ultimate challenge with a series of levels that are (as far as we can tell) completely unwinnable. Play Tantalus, doomed to forever hunger and thirst for feeding his son to the gods! Experience the plight of the Danaids, who must fill a sieve with water! Zeno's Paradox may not actually be a mythological punishment, but we're willing to let that slide.
Once you're done having your liver ripped out by an angry bird, you can check out the other games on Barr's website, including Safety Instructions (or "Mavis Beacon Teaches Horrible Death In An Air Wreck") and Let There Be Smite!, which puts you on the other side of the god/sinner divide. Or maybe after all that torment, you just need a nice, relaxing game of QWOP.