I've fallen in love with Dungeon Crawl Classics RPG. My first impressions of actual play can be found here.
I had planned on running DCC as is - for a couple of sessions, at least
-, but I just couldn't resist tinkering with the rules.
My house rules have since evolved to the point of a nearly total rewrite. The only part of DCC I use without changes are the spell tables.
I'm afraid my house rules have become too complex to post them here anymore.