Open Source (e-File) Tax Return Software?

If you're an American, it's getting closer and closer to that date we all have come to know (and dread)...tax time! To this end, Weston Hopkins asks: "I am filing my income tax return again this year and was looking at the IRS's e-file option. They list many software companies but I have found none that are free. Does an open-source e-file tax filing project exist?" and a more general query from DarkClown, who is looking for an Open Source equivalent to Turbo Tax. Have there been significant changes in this area since the first time this question was asked?