The Seven Day Roguelike Challenge has been a reliable source of weird and wonderful experiments for years. This year's event has now come to an end and while entries often receive extra polish or fixes after the deadline has elapsed, you can read about and download the games right now. I've only played a handful but will check back when the voting results are in. For now, I've picked out two games that represent the breadth of entries well. Creek Hero is a survival horror game that plays out like a handsome roguelike adaptation of Spore's first stage, and NoirRL is a semi-scripted ascii detective adventure.
I haven't actually made any real progress in NoirRL but, if memory serves (and it often doesn't, leading to an internal fracas), it's the first detective roguelike I've ever played. Press '?' to bring up a list of commands and check your telephone before leaving the first room. When I realised I could leave New York and wander around a map of the USA I was pretty much sold.
Creek Hero is simple. Eat smaller fish, avoid larger fish. There's something agonisingly tense about planning a safe route as the creek becomes increasingly hazardous though. You can always see the direction a fish will move next and eventually you'll resort to darting between gargantuan creatures as they feast on one another. It starts slow but rapidly becomes compelling and weirdly horrifying. I was joking when I said described it as a survival horror game but it was a very serious joke. The little spurts of blood send shivers down my spine.