Accentuate the Positive by Bing Crosby and the Andrews Sisters.
I have just tried to find it on Youtube, but can only come up with a distinctly second rate version by Bing Crosby with Bette Midler. Much though I like bette midler, it just isn't the same.
It is a song which always had my then teenage daughters singing along in the back of the car. It might be off limits because there are very briefly some possibly politically incorrect spoof black southern accents on it... but if you can cope with that, it is a wonderful upbeat piece of music.