Since NCrunch has left the free market, I was looking for a similar tool for code coverage marking, and continous testing like NCrunch
edit: I'm using VS2012
update:
I've been using ContinuousTest for a while now, it's OK, but I think it lacks feedback when I write code. The feedback is good when I write tests, but when I break a test (while editing source code) it won't tell me that the test broke (in the margin, like it does for NCrunch). So if anyone knows other tools, I'm still listening.