Interesting Challenges?

Anyone have any interesting self-imposed challenge "modes" they've been having fun with?

I've been taking a break from endgame and building and just trying some fun rush playthroughs that I can either complete (or fail, mostly fail) in one or two play sessions. Just looking for some inspiration. Have done the no bosses thing, but that one doesn't really have a completion goal and I never minded raids anyway.

A couple recent ones I completed:

No Death, 15-day Bonemass rush. Kill Bonemass before the start of Day 16 without dying. This one took 6 tries. Try 5 I died to Bonemass, which was more than a little aggravating. I found this challenge really good in general for getting better at spending time only on the things that are important to progress. I think 20 day Moder is possible, but would require more luck on placement – I've had maps where I spent more than 5 days just looking for Moder, whereas it usually only takes a few sunken crypts to find Bonemass.

10 Day Wolf Taming Challenge. Tame a wolf before the start of Day 11. Pretty repeatable, actually, for standard wolves, managed to get a 1 star, trying for a 2 star now, but it's so random if you get one I'm not sure it's worth sticking with. Melting the Elder with 10+ wolves while still in Tier 1 gear is admittedly pretty satisfying, but they're so bad against Bonemass that the idea itself is kind of a dead end – you've got yourself an army of wolves you spent time building up at great peril to your viking which is pretty useless until Yagluth.

Anyone have anything similar they found interesting and/or useful? I like both of those things.