In the first 3 weeks I did nothing (I had an episotomy & tearsing & lots of stitches so it hurst too much)
Now if the weather is nice I'll go for a walk for 1-2 hours or if its cr@p & I still want to go for a walk I'll go to the shops. Some days DD is fine to lay on the floor or pram or whatever while I have a shower & get sorted, other days she's sooky & just wants to be held so I dont end up having a shower until DF gets home from work but Ill still put her in the pram & go for a walk.
We have wiifit as well but I havent used it yet since I gave birth because I still havent had my 6 week check up (its next week at 9 weeks!) and I wanted to make sure my stomach muscles are up to it before I try & do it & hurt myself.

At this stage DD sleeps from 1-4 hours at a time with 1-3 hours of waking inbetween, so you do get time to do stuff its more if you can be bothered IYKWIM

HTH