I'm really fond of crazy quilts, so all of my "bummer", extra, and test blocks end up in my crazy quilts. Sometimes I leave the blocks intact, or if I have several (like you do) I just grab my rotary cutter and slice them up into random shapes and sprinkle them throughout the quilt.
Crazy quilts are awesome for using up weird little scraps and odd blocks. I make at least one a year and I really look forward to making them. Anything goes, and it's nice non-stressful sewing. People seem to really like looking at them too - family members often spot scraps (or entire blocks) from quilts I've made for them. I think they're my favorite type of quilt to make. Plus I have space in my scrap bin afterwards!