I've encountered a very, very strange error. Whenever I type a command, I must press enter several times before the Terminal executes the command. Note that this is not a hardware error: I can still the newlines appear on the screen, but Terminal, for whatever reason, doesn't handle it correctly.
For example, typing "rails server" must be followed by around 4 presses of enter, and the title of the Terminal changes from "bash" to "env" to "ruby" and then to "sh" and then to "ruby" again before anything happens.
Similarly, commands like "git -v" don't even work anymore, as pressing enter somehow aborts them.