Both females right? You can give them things like toilet paper rolls to play with, or even ripped up strips from old phone books (they love dragging it around and building sleeping nests with the stuff....great way to recycle old phone books too). Old shoe boxes or big kleenex boxes with a couple of holes cut out (they'll chew more too) make fun places for pet rats to explore. Eventually you can even buy a glass tank topper (made of rodent safe wire) made especially for rodents that give them a second level to play on and expand their available living area. Make sure to provide lots of hard food or things to chew on....rodents teeth never stop growing. Don't offer any head lettuce (it's all water), other greens are fine in small amounts...too much and they get the runs (yuck!). Mine love the big bag from GFS that's called "Spring Mix" as a once in awhile treat. They are great for eating up all sorts of kitchen leftovers....chicken wing bones being a huge treat for my colony for instance. I just keep a covered icecream bucket in the fridge marked RATS ONLY and put all sorts of scraps in there for the rattie crew.

Pet rats are great fun. They are extremely sociable and quite loving to the humans they know. I'm glad you are getting a second one as rats get very down if they have to live alone.