If I was real ambitious I would make a quilt, pillow or other such large surface with itty bitty tiny squares. Oooh, I do like that idea! The opportunity for pattern is pretty enticing. I particularly like the quilt up there, but a "postage stamp" solid scrap mini quilt would also be lovely. Dare I?
Christina's patchwork bunny ornament has that same captivating look (tutorial here). Not quite a scrap buster, but it would put a dint in my scrap jars.
I think that a ticker tape quilt, like Penny's, would be the quickest, most thorough scrap buster. Raw edges = fast. And, I like that you could work it up block by block as time goes by, and that it uses random sizes.
And then there's this mini flag bunting. I've been wanting to make it for my kitchen for ages. Granted I'll have to be a bit picky about sizes and prints. My kitchen is not so eclectic that just anything would go. Hm. Well, using some scraps is better than none.
So, what is your vote for my bottled rainbow?