Just wondering how everyone entertains their toddlers when trying to get their baby to sleep?

DD1 is 2 yrs 3 months and DD2 is 3 months. I have to rock DD2 to sleep. Sometimes I put her down but she only sleeps for about half an hour so I have time with DD1 to do things then. But after that she needs a longer sleep so I just put her in the HAB. Then I feel though that I still can't do things with DD1 because she wakes up if I'm too loud or bend down, etc. And I'm also not sure what to do with DD1 when I'm getting DD2 to sleep. It's much easier if I go away from her into another room and bounce on the fitball. She goes to sleep faster and I'm free to go back out with DD1. But I feel bad like I'm always just leaving her to entertain herself! Luckily she's good at it.

So any tips or ideas would be good?
i could have writen that word for word, including the fit ball, wish id thought of using one with dd1, hours of rocking/bouncing/walking with her ruined my knees!
....i normally get a few things out for her to play with, some puzzles and pens etc, if dd2 is taking to long to go to sleep and dd1 is getting bored i put the tv on. but thats the extent of my tricks!!