This is their current set-up(tad messy as they like to nest in the top level):
In this pic you can see, my marshall bandit bridge in the top(got it on eBay, it's basically the only non-pocket/tube/hidey-hole hammock they'll sleep on so far), there's also a bunch of chews up there, a seed block & one of 3 food bowls.
2nd Level has a log bridge I got them recently from Ranch House Cages, the rattys love it. You can also see their salt lick in the far right corner.
Not much down the bottom today, just a corner hammock, a couple of rope perches, food, water & the orange ball things you can see is one of two rope/wood bird toys in the cage at the moment.
I'm hoping to upgrade to a Ferret Kingdom cage next year, but for now my rattys seem quite comfortable & they get play time everyday(and extra play time when I'm overwhelmed by their insane cuteness :P). Soon enough they'll be bigger & won't be able to escape from my playpen, then they can play for as long as they like :P Crazy little escape artists....