Oh that's a great idea. Thank you! I have garbage bags full of 2x4, 2x3 and 2x2 bricks in common colors that are worth relatively little. I'll ask my panel of experts (5 and 7 years old) to see what they would do with such a treasure trove.
I've looked on eBay, but most of what I see in bulk there are lots of just one size or one color bricks, or just pounds of completely random pieces. I'd love it if I could find something like an assortment of 1,000 mixed 1-by-1/2/3/4/6/8 bricks in 4-5 colors, or the same with 2-by-N bricks.