Without totally renovating what are some quick things, to make your home baby safe?

Our niece and her husband are coming for an overnight visit, and they have a two girls a 3 year old and a one and a half.
Besides putting breakable things out of reach, what other things can we do?
We bought a pack of zap straps to lock kitchen cupboards and under the sink, we will just cut them off when they leave.
Also what would be a non messy treat, that everyone can enjoy children and adults and keep little hands clean and not sticky from touching everything?