As I think most of us have, I have played this game to death. I love it.
I have embarked on mountains, beaches, tundra's, deserts and swamps with aquifers. I have taken a leaf out of Sphalerites book of farming the ocean (specifically for sea serpents) with cage traps, and half-successfully colonised the Circus (eventually ended with !FUN!), I've even done a one military dwarf at a time challenges. I have done a few one pick challenges, and a bunch of above-ground only forts. But now I spend most of my time making forts just for use in Adventure mode. I need a new challenge to attempt (and hopefully fail many times at).
I'm currently embarking on an Evil Glacier biome, but can any of you suggest any new ways of playing?
Challenging, or just interesting and fun, all suggestions are very welcome and encouraged.
EDIT: Also, can anyone suggest interesting things to try, or methods of play, like making above ground forts, surface-only farming/food gathering, cavern-colinising, domestic animals only, etc?
The hardest kind of embark would be the no-supplies-on-a-glacier embark. If you do not have access to any other biome, then I can see it becoming a very difficult embark indeed, because you only have three logs from your wagon and the two animals driving it. Without any water or plants to make alcohol, you cannot make anything to drink. The only way to survive is to make it to the first migration wave, and hope a miner comes (else you will have to savescum).
You can make this more survivable by embarking with a large enough amount of booze (and possibly food as well) to last to autumn.
A better kind of survival challenge will provide you with the tools to survive (i.e. picks and an anvil) but require you to find the items you need, i.e. dig through the ice, find stone to build with, find a cavern to get plants and seeds.