This easy-to-miss Steam event has dozens of great roguelikes, including my number-one pick for the genre's most underrated RPG

gamesradar.com:

The folks at volunteer organization Roguelike Celebration have set up a Steam event uplifting all things permadeath and procedurally generated, and the easy-to-miss festivities have also collected some solid discounts on some of the best roguelikes around. 

This roguelike Steam event is a third-party thing and not an official Steam sale, which is probably why I didn't hear about it for so long, but there's still a good selection of discounts to pick from. The best one, for my money, is the 25% cut on Dungeons of Dredmor and its excellent DLCs – still my pick for the most-underrated roguelike of all time. Move fast, too, because this discount ends in just over 24 hours from the time of writing. 

Dungeons of Dredmor is a classical turn-based, tile-based, dungeon-crawler RPG. It was released in 2011 and has aged like the finest wine. It's simultaneously one of the funniest games ever made – quirky but not loud or obnoxious about it, instead presenting absurdity very seriously – and a mechanically engrossing masterwork that gets to the heart of the original Rogue in a much more approachable way while still being hard as all hell. 

Dungeons of Dredmor's greatest strength is its unpredictability. Absurd traps, items, monster designs, and shortcuts keep you on your toes every run, and each excursion feels meaningfully different thanks to a peerless skill system. You've got staples like sword and axe-wielding, perception, and alchemy, but that's the boring stuff. I'm talking about Emomancy, Communism, Killer Vegan, Paranormal Investigator, the Werediggle Curse, Viking Wizardry, and Magical Law – all fully fleshed-out and genuinely useful classes with multiple sub-skills, and just a sample of the absurd builds you can think up.