[Buster Bailey]

I haven't heard of too many toys that are safe to leave dogs while they're unattended - and I don't like to give a lot of treats (don't want them to get fat!). I just got my babies' puppy play pen all set up in the basement so that is where they're at while I'm at work now versus their crate (I come home over the lunch hour). Just wondering what people leave for their furbabies to keep them from getting bored when they're left alone? Buster & Bailey are 8 months old now. Any suggestions would be appreciated!