Make 'em and hide 'em.
Our dog got one of those huge muffins (the kind you buy at Costco) off our bottom shelf in our pantry the other day. I swear he ate it in one gulp.
When I was in 8th grade, we had a science fair going on. For my project, I had gathered a whole bunch of differant types of store bought bread (and one home made sample) and put them out to see which ones grew mold the fastest.
On the morning of the day I was supposed to turn the project in, our Rottie got onto the counter and ate everything.
I got bonus points for originality in actually using the "Dog ate my homework" excuse.