I've encountered many unique floors built by my customers. People who shop at demolition sales are a resourceful bunch. On a big job that produced lots of heavy timber, there was no time to fiddle with low value 2x4s which were given away. One guy gathered hundreds of random lengths and laid them flat on a good subfloor. This super durable floor was built for the cost of nails, varnish and rental of a floor sander. He spent about $1 per sq. ft. and has major bragging rights amongst the woodworking crowd.