Is it 2x4 in inches or feet?
Make an island, or make a free standing chopping block with legs, or make a rolling bar cart.
You could make cutting boards. Would also make a nice table top or coffee table top. Just protect it with some clear water based poly. I would make sure it is formulated so it won't yellow over time. Sliced into thin pieces it would look good as a backdrop of pictures or metal artwork. It would lend a farmhouse look.
Cutting boards would be my choice.
Some like cut outs of their states shape. A look around etsy might give ypu more inspiration.
Oh, fun! Lots of things I imagine. You could make a rolling cart and use the block for the top or use it as a sort of shelf/desk/small eating area in the kitchen and put a stool under it, make shelves out of it.