I like the way this app can even make an a-musical loser like me sound like a pro! VidRhythm gives you a nice selection of songs and all you have to do is record some basic noise. I can do that! You like me singing to you? Shall I sing more often?
Oh! And an even more hilarious one can be found here. Watch it and then you also know why I am so happy with my brother in law!