Rcov are hurting many people because of a segfault when used with rspec. Fortunately Tom Copeland wrote a patch last week. I patched it against rcov and put on GitHub. You can install it as a gem doing like this:

$ gem sources -a http://gems.github.com (you only have to do this once)
$ sudo gem install mergulhao-rcov

Someone knows how to make GitHub recognizes my README.markdown file?