DIY stacked wood fireplace facade -- I actually really love this idea even if you don't have a fireplace to begin with. It'd be so simple to zazz-up a brick or stone wall with a faux fireplace to create a gorgeous feature wall.
Anti-slip remedy for rugs! Rather than buying expensive anti-slip mats for a rug, just turn it over and run a few lines of acrylic-latex caulk every 6 inches or so. Let dry and flip over and your rug wont be going anywhere!