Way better than plain ole gate! Little Bit of Paint: DIY Baby/doggy Gate. Less permanent than some of the framed gates I've seen. Wonder if I could use a little trim for the top and a door I already have cut in two?
Add a strip of trim a bit above already existing baseboards, paint between, and you get faux thick baseboards! Other good ideas here as well. 31 Easy DIY Upgrades That Will Make Your Home Look More Expensive