In brief: We've seen plenty of people completing Souls games while blindfolded and using Guitar Hero drums as a controller (or something to that effect). But if you want a real challenge, try completing a no-death LASO playthrough of Halo 2 Anniversary, a feat so difficult that one streamer is offering $20,000 to anyone that can achieve it.
Finishing Halo 2 on Legendary difficult is no simple task, especially if you're trying to do it without ever dying. Once you add the challenge of turning on virtually all the skull modifiers, the run moves from incredibly hard to nigh-on impossible.
Secret skulls have been part of the Halo games for most of the franchise's long history. They contain modifiers designed to make the game harder, such as turning off the radar/entire HUD, increasing enemy difficulty, and halving the amount of dropped ammo.
Streamer Charlie 'Cr1tikal' White recently set a challenge for someone to complete a deathless 'Legendary All Skulls On' (LASO) Halo 2 Anniversary run. The only modifier that isn't enabled is one that benefits the player, 'Envy,' which gives you invisibility instead of a flashlight. Such a feat has only been achieved once, by 'Jervalin,' but it was done with Envy enabled.
So confident is 'Cr1tikal' that nobody can complete this challenge that he offered $5,000 as an incentive. After several weeks of no successful attempts, he raised the bounty to $20,000 and provided some advice to those who want to try. "I've actually tried it myself; I could not get past the first two rooms in the first mission of Halo 2 with LASO!" he said.
If you consider yourself a gaming god and would like 20 grand, here's the form to enter the challenge. Note that the achievement must be streamed, and VOD must be uploaded.