At that age, my dd liked to sit in her high chair while I did chores in the kitchen. I could give her almost anything...LOL...a paper cup was her favorite thing!
There are lots of cause/effect things that I would put on the tray for her....she had a little fabric books, stacking rings, teething toys. She really liked her excersaucer at that age also....she loved to look at the toys that were attached. That always bought me a solid 20 minutes.....that was how I showered each day....!
Another thing that she loved was her baby feeder.....we'd put a slice of apple in there and she was happy as could be....I could sweep the whole kitchen and load the dishwasher while she gnawed away on it! She may have been more like 7 or 8 months....but it was the greatest thing!
http://www.babysafefeeder.com/